C2ndLTpigeon
Mopar or no Car!
That was my other question if I used a pair of 360 heads will it boost compression? And will it change anything else like valve to piston interference, push rod length etc?
Here is the specs on my camshaft
318 Port match heads to Performer RPM Intake
- Thread starter C2ndLTpigeon
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That was my other question if I used a pair of 360 heads will it boost compression? And will it change anything else like valve to piston interference, push rod length etc?
Here is the specs on my camshaft
mini
Small Bore Long Stroke
Open em up
C2ndLTpigeon
Mopar or no Car!
Were those stock like my heads? If so wow!
mini
Small Bore Long Stroke
302 peanut port heads yeup. Made great power
glhx
Well-Known Member
Can you post more detailed pictures of that
86 to 91 dodge 318 closed chamber heads:
302
714
645 are all the same head castings.
If you can find some good cores, you can put new valves and seals in them. They have the hardened seats too.
Rock Auto had nice reman sets available, but they have been out of stock now for about 3 months. Can put your email in with them for when they become available again, no commitment to buy.
Mr Gasket #1121G thin head gaskets .028 ths compressed thickness for the 318s.
302 and 714 casting numbers for the 318, same heads.
Can tell them by this rounded raised part of the head casting between the spark plugs when they are still bolted on the engines.
If you are looking for power do NOT waste money on 302 heads....the ports are tiny, don't flow much, and are not good for power focused builds. They do work fine on stock, low HP builds (like for trucks, daily drivers and such).
For what its worth, I did a head comparo years ago between some home ported 302's and some home ported J's on my old 318. Long story short, the J's were over half a second faster at the drag strip on that little 318. If you are interested in making power, spend your money on a good after market head (Edelbrock, Trick Flow, Etc).
For what its worth, I did a head comparo years ago between some home ported 302's and some home ported J's on my old 318. Long story short, the J's were over half a second faster at the drag strip on that little 318. If you are interested in making power, spend your money on a good after market head (Edelbrock, Trick Flow, Etc).
PRH
Well-Known Member
I started doing some 318 oval track motors in 92/93.
Some of the rules were stock heads with 1.88/1.50 valves, 10:1, stock iron 2bbl manifold.
The owner had lapped up the MP 302 head propaganda and had been running them the previous year.
I bought my first flow bench and started doing some testing.
I couldn’t see any reason why the 302’s would be better in a race application like what this was.
So, for the first trip to the dyno a head swap was going to take place.
302’s vs 596’s, both set up for 10:1cr, both had 1.88/1.50 valves.
The 596’s were about 40hp better.
That was the end of me messing with 302’s.
For something in the 300hp range, they’re probably fine........ but they aren’t something I’d spend a bunch of time on.
Some of the rules were stock heads with 1.88/1.50 valves, 10:1, stock iron 2bbl manifold.
The owner had lapped up the MP 302 head propaganda and had been running them the previous year.
I bought my first flow bench and started doing some testing.
I couldn’t see any reason why the 302’s would be better in a race application like what this was.
So, for the first trip to the dyno a head swap was going to take place.
302’s vs 596’s, both set up for 10:1cr, both had 1.88/1.50 valves.
The 596’s were about 40hp better.
That was the end of me messing with 302’s.
For something in the 300hp range, they’re probably fine........ but they aren’t something I’d spend a bunch of time on.
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69 318 with LD4B aluminum 318 intake and 302 heads.
1991 318 with 302 heads and TBI cast iron intake converted to 4 bbl application. 91 stock intake is more of a factory high rise with a bigger Plenum.
For some of these basic drivers and those that want a 4 bbl can do the 2 to 4 conversion. Not for everyone but they actually work quite well for a driver.
It's hard coming up with small port intakes for the 318s, so this is one alternative that I like that gets the 318 intake ports matching to the 318 heads.
91 stock TBI intake on left, more of a high rise and bigger plenum.
74 stock intake on the right
Both work as an alternative.
1991 318 with 302 heads and TBI cast iron intake converted to 4 bbl application. 91 stock intake is more of a factory high rise with a bigger Plenum.
For some of these basic drivers and those that want a 4 bbl can do the 2 to 4 conversion. Not for everyone but they actually work quite well for a driver.
It's hard coming up with small port intakes for the 318s, so this is one alternative that I like that gets the 318 intake ports matching to the 318 heads.
91 stock TBI intake on left, more of a high rise and bigger plenum.
74 stock intake on the right
Both work as an alternative.
PRH
Well-Known Member
How about a pic of the TBI intake without the carb on it.
I’d like to see what you’re starting with.
I’d like to see what you’re starting with.
U loose compression with the 360 head on a 318. U should change pistons to get the compression back up. Kim
Ive done this before and with very good results. The intake starts making more power a few more rpm up the scale than the Performer and the like. BUT, unless you have steep Hwy gears, not only will you not really notice much at all but you’ll also just simply buzz through the first few hundred rpm quickly. I know this from the LD-340 as well as the RPM-AG. It’s nothing...
This is not true. In truth, the Performer and the RPM are both really excellent down low. The Performer just gives up on top a wee bit in HP and total usable RPM.
The Performer is just like the OE 4bbl. And does very well. Not really any better or worse than the factory OE unit. The Weiand Action Plus and Stealth fall in between the Performer and the RPM. Having all of these intakes at one point, they all did well.
Most people give the Performer and the stock OE 4bbl a unfair bad wrap and a handicap without merit. There really is t a reason you can’t pull 400+ HP out of ether or these intakes. Never mind a porting.
That kind of set up is a good one. It skips expensive rebuilding (if it s not needed of course) and pistons. As high school kids and early 20’s, a lot of us did that. It helped the handicapped smog era mills pretty good. Not great, but it worked well enough.
Good question. Search the threads! There was a discussion on this very thing not to long ago.
MOPAROFFICIAL
Oogliboogli
MOPAROFFICIAL
Oogliboogli
You can lose compression, but not if they are the same chamber volume.
The 302 are 64cc. 360 heads range 70-72cc,X heads are around 69cc.
302 head ootb flows less than an open chamber 318 head and 273 closed chamber heads. They are just a chamber..and even that shrouds the ever living **** out of the valves. They need a ton of work.
OK, here you go
91 TBI stock 318 cast iron intake, left
74 stock 318 cast iron intake right.
The 91 intake has quite a few improvements over the 74 intake.
Both are Dual Plane intakes so that is a good thing.
Like the underside of the 91 also, nice and clean and they did away with that insulating tin that holds carbon chunks like came factory on the 74 intake.
74 intake underside with the insulating tin permanently removed and carbon chunks cleaned out.
Drilled and tapped the 91 carb mount area just slightly larger than the earlier stock 318 2 bbl bolt pattern to fit the 4 bbl adapter best, and get the threaded holes in the best spot on the plenum.
91 4 bbl adapter
The 74 intake uses the stock 2 bbl mounting threads for the 4 bbl adapter.
PRH
Well-Known Member
Well ...... the valve rule was 1.88/1.50....... so that’s how the heads were set up.
302’s don’t come with 1.88 intake valves either....... yet that’s what I put in them.
I’m sure you could figure out how to get a 1.50 ex valve in a 360 head.
No one is claiming this is any sort of speed secret.
The heads were set up this way to fit within a specific set of rules, and to see which head combination made more power, within those rules.
318 heads with 1.88 intake valves, or 360 heads with 1.50 exhaust valves........ with the heads being the only thing changed.
The test was done on the dyno, back to back, on the same day.
With the heads in those configurations...... the 360 heads crushed the 318 heads....... on that motor.
There would have probably been an even greater power discrepancy if the 360 heads had used the 1.60 ex valves.
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LA 360 heads do use 1.60 ex valves. Kim
PRH
Well-Known Member
The divider is half missing on the TBI intake from the factory?
PRH
Well-Known Member
Which has little to do with anything when the rule stipulates the heads have to run a 1.50 exhaust valve.
You have two choices, put seats in the bigger heads so you can make them fit the rules....... or run the small heads that come with the 1.50 valves.........and give up the 40hp that comes from using the bigger heads.
I went with putting seats in the bigger heads so they could use the 1.50 exhaust valve.
Yep the 302's are pretty damn close to the 273 heads. A good 273 replacement with hardened seats but no big hp gains. The induction hardened seats go away if you grind on them too much for bigger valves. A moot point with a 273 anyway with the small bore and valve shrouding. (and bore notching for the intake side) I wonder if the 1.50 exhaust would benefit much with a 1.60 and leave the intakes as is.
PRH
Well-Known Member
If I were playing with those intakes on “mild” 318’s....... what would be an interesting test to me is........
modding one of those to use a Holley 4412 on some sort of spacer/adapter where the transition was nice and smooth....... vs how you have it with the big step down from the 4bbl adapter to the 2bbl manifold.
Sort of a....... which is worth more?
The bigger carb.......or the “better” transition?
I thought I recently saw an ad for a 2bbl Holley Sniper EFI.
That probably uses the 2300 style mounting plate.
Edit..... yup.... here it is:
Sniper EFI 2300 2BBL - Holley Performance Products
Yes kind of fun to see what a person can do do make things work here. Thinking that 91 manifold and 4 bbl adapter is going to work out nice on this 318 here. Stock flat top pistons .040 down in the hole with the thin .028 ths head gaskets and fresh 302 closed chamber heads. Real close to 9.5:1 cr.
The main reason I am looking into these is that I put the same 2 to 4 bbl kit on a '69 Satellite Stock 318 with the factory 9.2:1 pistons.
Really woke up and made it start and run real nice too with 1406 electric choke Edelbrock on it. Did not have to rejet a thing, just ran nice. Even the tone of the engine deepened up listening to it idle with the hood open. Now the engine was getting the fuel that it needs instead of running that economy factory 2 bbl.
Then there was the added fun and additional performance of the 4 bbl.
Pulled real nice even in the bigger B body car. 2.94 gears behind a 727. Freeway speeds not a problem, want to pass someone just open up the four barrel and you are good.
Was such a nice upgrade to the Stock 69 Satellite, made a real nice driver out of it. And did not have to pull the intake or change the cam.
So yeah will be fun to see how this next one works out on this Roller 318 Conversion to 4 bbl and manual fuel pump.
Here is the '69 Satellite with the stock original 318 and the 2 to 4 bbl conversion kit with the 1406 Edelbrock 4 bbl carb.
Ran out real nice, only 37,000 miles on the car at the time.
Old 2 bbl carb setup
New 4 bbl carb setup
Ran out real nice, only 37,000 miles on the car at the time.
Old 2 bbl carb setup
New 4 bbl carb setup
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