X O U or J heads on a 416?

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swinger340

swinger340

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Has anyone tried stock mopar heads on a LA stroker motor? If so what kind of power did it produce?
 
What kind of power did they leave on the table ?
I imagine you could build a 416 and tailor the cam and top end to make use of the small port high velocity......probably create a relatively low r.p.m. torquey sumbitch too.
But a motor is still an air pump at the end of the day.
More air in , more ooomph out.
Years back I did some business with a builder who created a pair of 460 Fords that made peak torque at something like 1800 r.p.m. , they were destined to power generators in a large motor yacht. Had cams custom ground and spec'ed everything specifically to where these things were going to be run.
You can certainly use factory iron heads , though I'd definitely have them ported so they didn't choke things too badly.
You could probably do the calculations and get a ball park using this formula .......drop down to the H.P. from air flow and it will give you a pretty fair idea of what to expect.
Certainly enough power to make for a stout street car , and it would probably have reliability built in due to the restrictions the heads would place on the combination.
http://www.wallaceracing.com/Calculators.htm
 
I had X-Heads on my 418 with stock HP exhaust manifolds. Engine dyno peak power of 393 HP @ 4900 RPM and 472 Torque @ 3700 RPM. As stated above; it just couldn't pump any more air and ran out of breath around 5500 RPM. Heads had some bowl work and mildly ported.

Best of 12.96 with 3:55 and 2500 PMC converter on MT Drag Radials.
 
Dusterndart340 said:
I had X-Heads on my 418 with stock HP exhaust manifolds. Engine dyno peak power of 393 HP @ 4900 RPM and 472 Torque @ 3700 RPM. As stated above; it just couldn't pump any more air and ran out of breath around 5500 RPM. Heads had some bowl work and mildly ported.

Best of 12.96 with 3:55 and 2500 PMC converter on MT Drag Radials.
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What were the cam specs?

Was it dyno'd with stock HP exhaust manifolds on it?

I think HP and TQ per dollar, the stroker crank was money well spend. About $350-450 more than rebuilding your 340 with stock crank. Even with unported heads and HP exhaust manifolds.

You don't have to have the heads ported. Sure it will make more HP/TQ with ported heads. But so will your 340 with a warm cam.
 
" We ended up with 501HP @ 5600rpm and 498TQ @ 4400rpm

With 450+tq from 3000-5750 it will be super fun to drive. It idles at 850rpm with16 inches of Vacuum "
Quoted from MRL' s link.

Stellar numbers and staying under 6000 will help it live a long and happy life I bet.
I thought 500 h.p. might be out of reach.
Great job.
 
MRL Performance said:
I built this one last year with 596 heads. I make pretty good power.

http://www.forabodiesonly.com/mopar/showthread.php?t=189991
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WOW..... That is awesome. I was thinking 450ish. I have a set of Ported X heads I would like to use on something, thinking they are not enough for my soon to be 416. As we already talked about my goal is 500/500 or a tad better. The X heads flow 250 @ .550 Not outrageous but they were done for a 340 build. May just sell the X heads to help pay for aluminum heads. They were virgin low millage 69 X heads, new hardened seats, stainless Milodon valves, 5 angle valve job, valves back cut, new Comp springs max lift .550 130# seat pressure, gasket matched and bowl work.
 
danbobracer said:
I know this is an old thread but I have seen this build referenced several times in other threads and the link doesn't work. Could MRL or somebody chime in and tell me where I could read this thread?

Thanks.
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Guy went out of business years ago. Was known for "grossly" exaggerating dyno numbers. His engines typically made about 150 HP less than "advertised" backed up by real world testing.
 
I don’t know about the build or thread, but have run a best of 11.46 at 117 mph at 3353 lbs with X heads. 410 ci. With a good intake and headers maybe high 10’s?
 
replicaracer43 said:
Guy went out of business years ago. Was known for "grossly" exaggerating dyno numbers. His engines typically made about 150 HP less than "advertised" backed up by real world testing.
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my current shortblock he originally built. Got it very lightly used( one summer while guy waitEd on his hemi power train) from a guy on the other side of the state
the shop I use( excellent reputation) had to fix pretty much everything he touched on it.
Terrible bores, no fixture used, was tubed for roller cam, all the lifter bores on that side we’re wallowed out at the bottom, had to bush all the bores, on and on.
 
B3422w5 said:
my current shortblock he originally built. Got it very lightly used( one summer while guy waitEd on his hemi power train) from a guy on the other side of the state
the shop I use( excellent reputation) had to fix pretty much everything he touched on it.
Terrible bores, no fixture used, was tubed for roller cam, all the lifter bores on that side we’re wallowed out at the bottom, had to bush all the bores, on and on.
Click to expand...
Wow, amazing.
 
A friends street/strip brkt car, runs in our NSS class
'71 Demon, 340/416, stock 2.02 J heads, .475/.494" hyd. cam don't know @.050, approx 9.5:1?, TR with 2 650DP's, small hdrs, according to weight /mph makes around 420fwhp. Leaving over 100hp on the table with TF 190's and a .620 s/roller which its getting next year along with the rise in comp from the heads.
 
swinger340 said:
Has anyone tried stock mopar heads on a LA stroker motor? If so what kind of power did it produce?
Click to expand...
I ported a set of 1971 915 j heads. Spent months on them. They went from 160cc to 186cc... you don't get there overnite , that's for sure. At first a few went 270..others went 257-260's cfm...so I pulled the trigger on a flow bench.. and began working them till they all flowed withen 5cfm of each other.
No tesla, turbo this or tht ,Benz beamer super cars that the rich 'a wads' drive around here can touch it. Street or freeway... I will leave you. Never got it to hook all that great.lol it would break tires going 65 or so if I dumped it.
It flowed better numbers than a rhs head at the time, talking 249cfm by .400 lift... 270scfm at .500...hell the damn .300 numbers are in the 200's ...like 204cfm.
Quench tops and .030 p/h clearance.
Paper thin push pinches.
It's not whether or not you can make 500+hp with factory iron..its whether or not you know how and have the time.lol
 
MOPAROFFICIAL said:
I ported a set of 1971 915 j heads. Spent months on them. They went from 160cc to 186cc... you don't get there overnite , that's for sure. At first a few went 270..others went 257-260's cfm...so I pulled the trigger on a flow bench.. and began working them till they all flowed withen 5cfm of each other.
No tesla, turbo this or tht ,Benz beamer super cars that the rich 'a wads' drive around here can touch it. Street or freeway... I will leave you. Never got it to hook all that great.lol it would break tires going 65 or so if I dumped it.
It flowed better numbers than a rhs head at the time, talking 249cfm by .400 lift... 270scfm at .500...hell the damn .300 numbers are in the 200's ...like 204cfm.
Quench tops and .030 p/h clearance.
Paper thin push pinches.
It's not whether or not you can make 500+hp with factory iron..its whether or not you know how and have the time.lol
Click to expand...
I'm curious about something. Have you ever weighed a bare casting both before and after porting?
 
RustyRatRod said:
I'm curious about something. Have you ever weighed a bare casting both before and after porting?
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After porting, one pc bronze guides, hard seats both intake/exh, spring seats cut and .045 ish milled... they were maybe 2 lbs lighter. I don't know for sure but I can weigh them agaisnt some bone stock 70 castings I have. You can definitely feel the difference if you pick one up, but they're still iron. If they were ever to be that light 'like aluminum' they probably wouldn't last long once the engine warmed up LOL.
You won't see really good numbers out of a j head till it's about 175 CC's..or better. When I say good numbers I mean real strong low lift numbers as well as a decent Peak you can get a pretty decent Peak but have crappy Lilith numbers and that tells you your bowl is wrong or the valve job n lower angle isnt right/large enough . You can get 240s to 250 without getting into too much work.
Mainly stick to the classic 30 45 60 75 angles.
 
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The letter designation doesnt mean a whole lot. Its the casting number you should be looking at. The exception would be X heads since I believe they were always the same casting and used on early 340's.
I have had O and U TA heads. There were J's with 2.02 and also 1.88 intakes. Basically any 340 or 360 head would be a good start and there is not a ton of difference between them.
Personally I wouldnt bother putting stock heads on a stroker build. You would be way ahead of the game with a good set of heads, even on a stock stroke engine.
 
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