Anybody feel like clearing this up? Which cam and lifters?

[PhillH]

I'm building a street 1972 LA 360, so far I've decided to reuse the crank, rods, heads and hopefully valves. I've decided to go roller and am using PRW 1.6 shaft mount rockers, now I need to pick the rest of the valvetrain. I'm not going crazy on the cam, thinking around 9.5 to 1 cr. My goal is no less than 400 pounds torque and right in there HP. Looking for ideas. Thanks.
Also, I know the history of the motor, it's coming out of an RV and has 54,000 miles on it, ran perfect when parked but I havent started it in about 6 years. Not even going to try to start it.

 

[1wild&crazyguy]

Ideas on cam?
400/400 is easy.
Someone would have to be brain dead n order to miss that mark.lol

 

[PhillH]

Oh thanks, that cleared it right up.

 

[OldmanRick]

Are you thinking, hydraulic, solid or undecided? With the 1.6 rockers, lift will be easy to obtain. Most important will be matching the cam timing/duration with the final compression ratio. I'll nose around a little and see what's currently out there.

 

[FrostyMopar]

400ft/lb of torque is almost stock 360 territory. (edit, i was wrong. stock is about 300)

instead of going roller cam.. If you decide you would like to save $1000-$1200 and still make 400hp, the XE275HL is a pretty popular hyd flat tappet cam.

(roller cam, roller lifters and bushing the lifter bores, new pushrods...it all costs money!)

Should do it easy as long as you got 2.02/1.6 valves and a good valve job, good compression, intake and some headers.

I'm sorry I can't be of any more help, I've never used a roller cam and probably never will.

 

[rumblefish360]

You can use a small Hyd cam of approx 230*'s of duration @ .050 w/.480 lift and bowl ported heads to get what you want. No need for a roller cam unless you already have a roller engine.... Running.

 

[OldmanRick]

Are you thinking, hydraulic, solid or undecided? With the 1.6 rockers, lift will be easy to obtain. Most important will be matching the cam timing/duration with the final compression ratio. I'll nose around a little and see what's currently out there.

After looking at some of the off the shelf stuff, i'm thinking you may want to look into swapping the 1.6 rockers with someone for some 1.5's. The 1.6's are gonna give you way more lift (.550"+ range) then the stock 1.88 J heads can really use. There's always the option of talking to members, Brian @ IMM Engines (ou812) or Mike @ MRL (MRL Performance) about a recommendation or a custom grind.

 

[crackedback]

Look at this for some ideas on what it may take.
http://www.forabodiesonly.com/mopar/showthread.php?t=158426

You need some porting on factory heads to get there.

 

[PhillH]

Thanks Wild Crazy, I really want to do a roller setup, just like it better, but can I use the rollers rockers with a good hydraulic cam non roller? I don't know which to use hydraulic or solid, I need help there. Frosty I'm hoping to save a few bucks by reusing the stock valves. Just getting a good valve job and port matching. I understand hughs makes drop in roller hydraulic lifters? I'm still all over the board on this, please explain suggestions so I can understand why.

 

[1970Duster]

A retro fit roller setup ain't the cheapest (I have a full roller setup in my 340). Yes Hughes drop in hyd roller lifters work (it's the lifters I have in my block), but I believe MRL makes/sells a drop in solid roller lifters if you opt for a solid cam. Just make that which ever cam you opt for make sure it has an intergrated cast iron gear on it and run a harden intermiate shaft. Otherwise you have to run a bronze and you'll be ripping into your motor again.

 

[crackedback]

Getting 400 hp with a roller should not be difficult.

 

[1wild&crazyguy]

Thanks Wild Crazy, I really want to do a roller setup, just like it better, but can I use the rollers rockers with a good hydraulic cam non roller? I don't know which to use hydraulic or solid, I need help there. Frosty I'm hoping to save a few bucks by reusing the stock valves. Just getting a good valve job and port matching. I understand hughs makes drop in roller hydraulic lifters? I'm still all over the board on this, please explain suggestions so I can understand why.

The factory heads flow up to and peak in the .450/.500 lift range, opening the valves a lil more than that is the idea to a point...once you spend too much time and go too far into the turbulent zone you can get in trouble"flow backing up/reversion" more for less, in other words...so with that in mind the thought behind going beyond the lift/flow number u want is too get the valves open/close cycle 'which are sustained much longer than peak lift' close /around that flow@lift. That could be anywhere from .030-.100 above the 'hypothetically let's say its .480'..so if at .480 the port flows the let's say 250cfm, then something like .530 lift would be a good idea, that is if the port don't back up into the 215 cfm. Jmo

What heads?
Within the relm of stock, a 280 degree .500-.540 lift cam with 238-242@.050 would do it.

 

[PhillH]

Man I had to read that three times to understand that. lol. Is that taking in consideration the 1.6 rockers?

 

[skrews]

I'm building a street 1972 LA 360, so far I've decided to reuse the crank, rods, heads and hopefully valves. I've decided to go roller and am using PRW 1.6 shaft mount rockers, now I need to pick the rest of the valvetrain. I'm not going crazy on the cam, thinking around 9.5 to 1 cr. My goal is no less than 400 pounds torque and right in there HP. Looking for ideas. Thanks.
Also, I know the history of the motor, it's coming out of an RV and has 54,000 miles on it, ran perfect when parked but I havent started it in about 6 years. Not even going to try to start it.

I picked up a low mile RV 360 a while back. Thought to my self "right on" this motor won't need chit. Drop a cam in this thing, port the heads, replace oil pan and go. Not. Heads were cracked. Pulled a few bearings they were shot. Basically had nothing but a core. RV motors lead a hard life in a short time, often running hot, detonating up hills, and often poorly maintained. Don't know if you're rebuilding or just bolting on parts, but I thought my RV experience may give you some things to think about. 400HP/400TQ is an easy target. Cam, intake, headers, and maybe a little port work will get you there.

 

[PhillH]

Doing a full rebuild on it, but I've had this RV for about 15 yrs 54k miles on it and the motor has always been sweet, hopefully it will go smooth, I probably changed the oil after every trip, absolutely zero carbon or sludge in the covers and rockers.

 

[skrews]

make sure to have the heads crack checked (magnufluxed) before dumping time/money in to them

 

[Robbie2734]

Thanks Wild Crazy, I really want to do a roller setup, just like it better, but can I use the rollers rockers with a good hydraulic cam non roller? I don't know which to use hydraulic or solid, I need help there. Frosty I'm hoping to save a few bucks by reusing the stock valves. Just getting a good valve job and port matching. I understand hughs makes drop in roller hydraulic lifters? I'm still all over the board on this, please explain suggestions so I can understand why.

If I read this right, you're thinking about a flat tappit cam and roller rockers?? If so, it isn't a problem. You have to be careful the springs don't interfer with the rockers. This is not a 'roller" set-up.

 

[rumblefish360]

A Hyd. roller cam will use roller tappets.
A solid roller cam will use solid roller tappets
A solid cam will use solid tappets.
A Hyd. Cam will use Hyd. Tappets

You can use any style rocker you want with any cam.

 

[FrostyMopar]

I wouldn't recommend reusing the valves in your engine, valves are THE single most important part of an engine's performance. this is not a place to skimp.

on average the valve shape and quality of the valve job can attribute to 35% of the cylinder heads flow capacity. the bowl (or pocket) attributes to approx another 25%

After that you need to change the shape of the runners in the cylinder head itself, fortunately for you THIS part of the stock cylinder head will support your goal of 400HP.

But the high performance valves, good valve job and some bowl work would be a good idea

I have used Ferrea valves and would use them again, also Manley have a good reputation.

have you already bought the roller rockers?

IMO they're not necessary and the money might possibly be better spent on bowl blending the cylinder heads.

 

[rumblefish360]

Also, if you use a different rocker ratio, do so figure it in carefully. The bigger ratio effects not only the lift, but also valve spring selection and piston to valve clearance.

 

[pishta]

That motor has valve rotators on its exhaust valves so it would be best just to buy new stainless or back cut 1.88 intakes and 1.60 exhausts. 2.02 are fun but youll have to cut the heads for them and they are not mandatory for a 400 HP build. Mopar just made them to stay up with Chevy's 2.02's. I got an 86 truck 360 and it was beat. Ended up keeping the bare block and heads only.

 

[FrostyMopar]

I respectfully disagree pishta, I have never seen a 400hp LA build with 1.88 valves.

I'm not saying it's impossible, but I think the valves and seats are not good places to make compromises.

Phil, Bottom line for a 400hp 360ci build.

Stock heads. 2.02/1.6 Valves. light bowl blend.
High rise dual plane manifold (performer RPM, Air gap etc)
750CFM four barrel carb

Hydraulic camshaft should have approx 228-233 degrees duration @ .050" lift.
107-109 lobe separation angle.
.475"-.525 lift (that's with 1.6 rockers)

In all honesty I would ask a cam manufacturer about cam specs. they will ask you a bunch of questions and then give you a suggestion.

they usually know what they're talking about, so take their advice seriously. (Don't get enthusiastic and decide to over cam your motor!)

9.5:1 compression should be fine. Keep in mind you will need to measure this accurately with a beurette, Thick perspex and a dial indicator.

Regarding compression ratio, do NOT rely on manufacturer's advertised specifications. they will be wrong wrong wrong.

You'll need headers and a free flowing exhaust



Don't expect it to make 400hp from the word go, you'll need to tune it.

A large number of people assume their engine makes *** horsepower because the parts they used to build it are the same as they saw in a magazine or the same as someone else had in a fast car, that's foolish IMO.

An engine can easily fall short of it's potential. sometimes as much as 125hp down short at peak in a street strip car. this is often due to running an out of the box carb and distributor. it's actually reasonably common.

A motor can run perfectly smooth with plenty of punch below 4000RPM and still sound like a cammed up monster. The owner is often blissfully ignorant and happy to boast about the parts inside.

I also recommend the book "How to hot rod Small Block Mopars" by Larry Shepard.

 

[PhillH]

Thanks frosty that's sound really helpful, I'm definitely going to listen about the cam manufacturers advice once I pick one. I already have that book on my Amazon list,
I also decided since I'm no tuner it would be best to take it to a dyno for first run
And tuning, I know your right about that. The rockers should be here tomorrow, do you think I should leave the box sealed and return them for 1.5s? Or go for it whith the 1.6s?

 

[PhillH]

By the way, I finished pulling the 360 last night and its now in my garage on the stand!

 

[crackedback]

1.88's can easily support 400+ hp. Depends on the port/VJ in front of the valve head. Look at the EQ and rhs heads with 1.92 valves, they don't appear to have much issue getting over the 400hp hump.

The how to hot rod SB is a good book for general information. Some of the info, stock SB's blocks are only good to 400 or 450 hp... not so good.

Most cam companies will ask you some questions, if you are lucky, then go straight to the catalog to find a shelf cam to run. Sometimes there's nothing wrong with that, other times it's not a best choice. Another fun one, call the same cam company and talk with three different people, get three different grind suggestions.

Talk to an engine builder, lots of times they can get you a camshaft from the same companies for same and sometimes less money than from summit shelf stuff. Just depends. Ask Brian from IMM, Mike at MRL, JRob or any of the others that regularly build stuff and have manufacture access, they can get you a suggestion.