318 head porting for the average joe

Small Block Mopar Engine

  1. volaredon

    volaredon Well-Known Member

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    I have given up on cheap electric die grinders. I have a long body and 2 short body, Snap on straight air die grinders (hey that was what became available) plus a few angle die grinders. but I have never tried the angle die grinders on porting work. so far on the slant 6 heads I have done, these air powered ones have been the ticket.
    I have both long and short carbide burrs, and 1 of the short body die grinders stays at work. I use short body die grinder with long burrs and vise versa.
    for burrs I got a few from Fastenal, weren't terribly expensive. the rest come from a place online, look up Benchmark Abrasives. they have an awesome 10 pack (trial/sample pack) of various grit flapper wheels for a 4-1/2" electric angle grinder too. $10 for the sample pack.
     
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    • MOPAROFFICIAL

      MOPAROFFICIAL FABO Gold Member FABO Gold Member

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      They were determined to be "the shit" because they could raise the cyl pressure with their 64cc closed chambers compared to the open chamber heads which varied from 68-72 cc. Your 163 head came 72cc...so in your case the 302 closed chamber would raise the cyl pressure and yield more torque... but ultimately they flow the same.
      Nutshell=They aren't "the shit" , they are a closed chamber head that flows like most 318 heads and people use them to up the compression.
       
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      • volaredon

        volaredon Well-Known Member

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        Well, considering this thing has never seen over 4000 rpm probably since new, and probably won't while I own it. It's a nice cruiser and I will keep it as such, but I would like a lil more get up and go in the process.
         
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        • volaredon

          volaredon Well-Known Member

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          Considering that would it be worth swapping the 302s onto my engine or wouldn't it?
           
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          • MOPAROFFICIAL

            MOPAROFFICIAL FABO Gold Member FABO Gold Member

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            my answer is unique ..because I'm a head porter. I would not put them on any engine without porting them and doing plenty of unshrouding to bring out the potential.
            Do it, you want to...so go ahead. You'll gain some throttle response which depending on how your engine is tuned an runs 'in general' atm.. might be what you were looking for.
            The late model #920 273 heads in this thread are example of what to do with the 302 heads. BtwThose are up for sale by the original purchaser 'he sold the car'.. and has no use for them now.
            Whatever you ultimately do is for you to decide. You have the info.
             
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            • volaredon

              volaredon Well-Known Member

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              I wish I could have found a set of 920s..... but since its been over 50 years since they were made, I doubt it would be very likely that ID be able to.
              I want to port the 302s but I'm almost afraid to now that they have been thru the machine shop/ I may try it anyways while I'm working for teh one on my /6. That one is in line still for the machine shop.
               
            • MOPAROFFICIAL

              MOPAROFFICIAL FABO Gold Member FABO Gold Member

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              @540cuda
               
            • Torqueflite

              Torqueflite Well-Known Member

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              Parts in and of themselves are not "the shit" or "not worth a shit." All parts assessment needs context. Unfortunately, with a stock or very mild 318 in a nearly 4,000 lb '78 Fury it will take a heck of a lot more for you to feel the engine "wake up" than simply swapping one set of stock smogger heads for a set of higher-compression, heart-shaped chamber stock smogger heads with the same flow. In your case, the 302 heads are "not worth a shit." However, take those same heads and put them on a 318 in a 1964 Dart coupe and you might feel a slight improvement, but likely less feel than you would see some numbers change slightly on a time slip. In that application, the heads might be considered "somewhat worth a shit." Port them and match them with pistons, cam, intake, carb, converter, gears, and tires in that '64 Dart and they would be considered "the shit." Performance magazines and parts catalogues too often convince people that swapping out a single part equals noticeable gains, like the K&N filter craze of magically adding 35HP to a 2010 2500 over a factory paper filter; while the proud owner who just dropped big bucks on his unnecessary K&N filter will brag to his buddies that his filter is "the shit," even if that amount of HP gain were realistic in a stock application it wouldn't make a lick of noticeable difference in his 6,000 lb truck.
               
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              • volaredon

                volaredon Well-Known Member

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                well when I had my 83 D250 with its 318, I put a set of EQ Magnum heads, a stock 360-2bbl cam and a Performer intake and carb on there along with some Hooker super comp headers and it made a HUGE difference. HUGE. and I never pulled teh short block out of the truck, the bottom end had never been touched, with then 130K miles. this car has 56K original miles. I know that what I plan to do here is not exact same combo as that truck engine, with the EQ and magnum valve train 1.6 ratio//

                and this engine I am wanting to put these 302 heads onto, with a slightly different cam (looking at comp 252, EXACT same as stock 360-2 bbl cam except that it has 0.015 more lift... ) will somewhat make up for the difference in rocker ratio (that stock 360 cam's .410 lift became .437" with the 1.6 RR) with another Performer (maybe an Offenhauser, I have both, both are dual plane aluminum will probably make more difference which one is closer and easier to dig out, as the determining factor as to which one gets used) and a choice between a 500, a 600 Performer carb or one of a couple fresh ready to run TQ's that I have, plus a lean burn swap out, that I might wake this thing up at least "some".

                Note; I was looking at that 252 cam (I have a 260 here, wouldnt have to buy that) because EVERY spec is IDENTICAL in every way to the cam I put in that truck. EXCEPT the lift on the 252 is 0.015" more than the 360-2bbl cam. splits the difference between the 360 cam with stock rockers and the 360 cam with the Magnum's 1.6.
                I know that this Fury only has a 2.76 in it, Id like to go to like a 3.08-3.21ish (eventually) that truck had a 3.55 Dana 60 in it, never did anything with that, same rear end before and after.....
                I'm not looking for a race car with the Fury.... even waking up its stock engine, I don't see that car ever touching 4000 RPM. That' s just how we use it. but from idle to that point, it definitely needs some help in motivation department. we don't put but a couple thousand a year on the Fury, with covid and the lack of cruise nights etc it never came out of the garage last year. just looking to perk it up a bit, and I have what I have on hand, at this point. Worth a weekend of thrashing on it or a waste of a good weekend?
                 
              • MOPAROFFICIAL

                MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                There's a thread where I flowed the 302 head. It wasn't decent till the valve got passed the chamber side of the head, .500 or so.

                The cam could be marginalized by the shrouding. Take it to a shop and have them drop maybe a 2" stone intake and a 1 5/8-1 7/8 exhaust to unshroud them 1st, at least.
                Otherwise you're wasting the effort.
                Have them do a valve job like in my avatar... That's a 302 head just that valve job and unshroud, does like 190cfm. They can all do that.
                 
                Last edited: Jan 24, 2021
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                • Torqueflite

                  Torqueflite Well-Known Member

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                  What was the ET with the stock 318 setup versus the 360 setup or the dyno results with the stock 318 versus the 360 setup, if you have them? I certainly don't mean to suggest your are being dishonest since "in the seat" observations are extremely subjective, but I'm highly incredulous that putting a smogger 360 2bbl cam that craps out at 4,800rpm, 360 Magnum heads, 360 Performer intake, and Hooker Super Comps on a stock 318 saw noticeable gains in a 1983 D250. While a head porters and others on here might have the actual flow and dyno numbers, 318 cubic inches and a cam that doesn't make power over 4,800rpm in no way will flow enough to keep up with the 360 head/intake runners and Super Comp headers. That combo would seem to kill a 318 far more than make "huge" gains.

                  A 318 with stock 318 heads, Edelbrock LD4B intake with factory 318 runners, around a 340 cam grind with power up to 5,800 rpm, 650(ish) cfm carb, and full-length (not Super Comp) 1-1/2 or 1-5/8" headers with 2-1/4" exhaust would smoke the setup you describe comparing apples to apples. Do some porting described in this thread to those 318 heads and you'll see even more gains.

                  I don't envy your battle. A 4,000 lb car, torque-lacking 318, and 2.76 gears by design is a snail off idle but a highway flyer for sure.
                   
                • volaredon

                  volaredon Well-Known Member

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                  That 83 D250 was never on a race track, no ET available, but I had enough miles on it both before and after the head and cam swap and whether you want to believe it or not is your call. All I know is that it ran quite noticeably better after the swap than it had before. I doubt that that engine ever saw 4800 RPM. So that limitation you claim really didn't matter for how the truck was used.
                  I may have a chance to get it back, I sold it to my cousin a few years after the parts swap.
                  Maybe it wouldn't work for you but it did for me. Hauling and towing, was where I noticed the biggest improvement. About as far from racing as one can be.
                  It worked for me, well enough that I'd certainly do it over again the same way as the 1st time.
                  I didn't come here to brag, different things work for different people
                   
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                  • 66fs

                    66fs FABO Gold Member FABO Gold Member

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                    They use the same heads on 5.2 Magnum, 318, so I'm willing to believe you, who has actually done the swap. I could care less about Dyno numbers and 1/4 mile times.
                     
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                    • MOPAROFFICIAL

                      MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                      No one is taking that way at all, mo'power to ya, right?
                      Imo Different expectations for time and dollar spent would be more accurate.
                      The rest is just a obsession in ones mind of what is best for them regardless of anything else, like x heads or the latest this or that..'must haves' of any hobby.lol
                       
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                      • volaredon

                        volaredon Well-Known Member

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                        hey Torqueflite... what is wrong with Super Comp Hooker headers? They ARE full (and equal) length.
                         
                      • Torqueflite

                        Torqueflite Well-Known Member

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                        My point wasn't about dyno or ET times for the sake of racing or performance. Dyno and ET don't mean racing; they are scientific, mathematical methods to measure what part combinations/tuning do to an engine/car. I don't have a dyno, so when I make changes to components or tuning and want to more accurately gauge results, I have a stretch of road out in the boonies marked off at 60 ft., 1/8 mile, and 1/4 mile, etc. to give me different ETs. Atmospheric and road conditions will obviously impact that ET some, but it's a far better gauge than seat of the pants speculation and cheaper than paying for hundreds of dyno runs. When strangers on a public forum make claims about how changing parts leads to gains, if they don't have some form of scientific measurement as baselines of comparison, even if crude like my marked off road, it is conjecture/opinion. I examine and research it as such in an attempt to back it up with articles/publications/threads that in fact include scientific measurements before I jump on board. Just as I have not supplied scientific data to back up my claim that the OP's 360 combo on a 318 will harm it more than benefit it (I've never done such a swap because the scientific evidence I have found says it's a bad idea), I would expect others to look for articles about building 318s and about putting 360 parts on a 318 before trusting my advice.

                        One reason I like reading Moparofficial's posts on porting work is he shows and discusses the number comparisons. I doubt people would trust his advice as much if he simply said, "I ported these heads and the air coming through them feels and sounds like it flows much better." I certainly wouldn't be taking a grinder to my heads based off that assessment, but that's me.

                        Well said.

                        I don't think you came here to brag. Your initial question was about pairing 360 heads, 360 intake, 360 2bbl cam, and Super Comp headers on a stock 318 in a '78 Fury to "wake up the engine." My response was that combo will put the 318 to sleep versus alternative options. It sounds like you were set on your 360 combo as the hot setup before posting for opinions, so run the parts and enjoy the car regardless of what they actually do to the engine.
                         
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                        • volaredon

                          volaredon Well-Known Member

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                          Are you some kind of lawyer? Conjecture? As in you think I was BSing.
                          Wrong.

                          I have been down the "overcam" road before and after spending all I did on that one it has made me a bit gun shy when picking a cam for a given engine. I have a COMP 260 here that means I wouldn't even have to buy a cam but I think that might be a bit much for this combo.and, no, that wasn't the cam I had in my previous engine, that was too much.
                          That cam was an erson that I'd had back in the 80s.
                           
                        • Torqueflite

                          Torqueflite Well-Known Member

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                          Nope, not a lawyer, just educated in both vocabulary and knowing the difference between a fact and conjecture. Conjecture does not mean nor even imply you are lying. It means you've made some strong claims about "huge" gains without providing necessary evidence to support them aside from your personal observation. My comment about conjecture didn't apply to you specifically but to anyone making claims. It's clear you wholeheartedly believe in your claims, which is cool. I am incredulous (still not a lawyer) without seeing some baseline comparisons, which is also cool. No need to make it personal. This discussion is now way off topic from head porting, so have fun with the project.
                           
                        • 66fs

                          66fs FABO Gold Member FABO Gold Member

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                          Actually you are wrong on a few points. And I seriously hesitate to give my opinion because I don't like to get involved with this never ending debate with people who have not done something. First the OP wanted to swap 302, the last 3 casting numbers, heads he had done and setting on the shelf. Sorry, MOPAROFFICIAL for adding to the clutter of a nice informative thread. 302 heads are late 318 heads with a smaller combustion chamber, similar to early 273 heads. Without porting and chamber relieving, they flow the same as the original heads volaredon had on his low mileage Fury. The only thing he would be gaining is a slightly higher compression ratio. I'm not sure I would do the swap, all things considered. Once I'd get into it, lots of things would change. 360 heads on a 318 is a standard performance upgrade. If you do it right it is a big performance upgrade. I did more than I can remember, and even swapped them onto the 273 in my 64 Barracuda. A whole level higher in performance. Need numbers, not getting them from me, I was poor, no money for a Dyno and it was my daily driver. Same thing as swapping 351 Windsor heads on 289's and 302's. Same thing as swapping fuely heads on a SBC. Want to run on the street in the middle of nowhere, I'd give you a run, and beat most guys, and surprise the rest. It is the package and quality of the machine work. I didn't research it, I had friends that raced Stock Class and Super Stock Class, back when you could not touch the stock head castings. We got parts and just tried things constantly. Engines, heads, transmissions, rears, brakes, suspensions, what a blast!
                           
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                          • volaredon

                            volaredon Well-Known Member

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                            I keep hearing (and have for years) about 360 heads on a 318. While they have bigger valves (a definite plus) but also bigger chambers/ which further lower compression ratio (a huge negative) with all else being the same. "all else" being cam choice, manifolding, carb choice, piston depth in the hole, besides gearing, tire size and such.
                             
                          • Torqueflite

                            Torqueflite Well-Known Member

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                            Not knowing me or my experience, you presume much to suggest I "have not done something" simply because you disagree. You also take everything I've said out of context. Nowhere did I say "one should never put 360 heads on a 318" as you lead on. In fact, I used the example of how the 302 heads would be great heads on some 318 setups. My discussion was in the context of the OP's setup and desired outcome, which in no way will take advantage of the 360 and Super Comp components turning under 4,000 rpm with 2.73 gears as the OP says. Let's move on.
                             
                            Last edited: Jan 26, 2021
                          • 66fs

                            66fs FABO Gold Member FABO Gold Member

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                            Why would you keep everything the same? Everything is in the combination. I can get smaller chambers with 360 heads than your stock 318 heads. Power is airflow through the engine. If you cannot port heads, you run the best heads you can for the buck. And I am not telling you to get and set up 360 heads for your car. I already said I would leave it alone as long as it is running well.
                             
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                            • 66fs

                              66fs FABO Gold Member FABO Gold Member

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                              302 heads are 318 heads, not 360 heads. Read your last line, then reread my post#269. That is why I hesitate to answer some threads.
                               
                            • volaredon

                              volaredon Well-Known Member

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                              It runs good but it's just a dog. Starts easy, even though it still has its lean burn it had since new. THAT WILL be going away.
                              It loves cruising 70 down the highway, it just don't have any balls, can't hardly pass anyone if I need to. I rarely try to get it to much over 70, (it definitely will) but I am in town at lesser speed just as much as on the highway, and it needs help getting out of it's own way.
                              In addition to waking up the engine I'd like to swap to something around 3.08 gears.
                               
                            • volaredon

                              volaredon Well-Known Member

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                              As far as getting smaller chambers on a 360 head I don't want to have to shave enough off to introduce manifold sealing and fitment issues. At one point I had 2 ex squad diplomats. One 2 bbl the other a 4 bbl engine. I never had the heads off of either but the 2 bbl one had the 302 heads, the 4 bbl one had "360" heads, as it had "360" cast into the heads (besides the casting number which was elsewhere on the head) both had 904s (probably actually the 998 version of the 904, being mid 80s cars) and both had 2.94 gears. The 2 bbl one ran better than the 4 bbl one, it would run circles around the 4 bbl car. Even my 87 3/4 ton van, also a 2 bbl 318 with 302 heads, would outrun the 89 (the diplomat that had the 4 bbl) and strangely the van also had the same 2.94 gearing.
                               
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