416 compression advice

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Newf

Newf

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Hi All,

I'm in the process of having a 340 stroked to a 416 and I am wondering on what compression ratio would be safe for my application? I am putting a Eagle forged bottom end, H-beam rods, Mahle pistons with a hughes roller cam 242/246 @ .050 and would like to make it a daily driver. I will also be going with Edelbrock Performer heads, with hughes retro fit lifters, 1.6 roller rockers, smith custom rods and comp .600 springs. It will be going in my 72' Demon.

I would like to go with an auto tranny with a 2500-3000 stall and I'm thinking 323 or 355 gears. As I do not have a drive train yet I am still in the learning stages so any and all advice is welcome. The only thing that I know for sure is that I want it to be as powerful as possible and streetable on pump gas. The altitude in my town is 668 meters or approx 2100 feet above sea level.

I haven't decided what to put on the top yet but am up in the air between going fast EFI fuel injection or a 6 pack. What do you think? I am hoping for 475hp out of it.
 
I would go with 10.5:1, zero deck those pistons, and run a FelPro 1008 head gasket. I run 10.3:1 with mine with 20cc step dish pistons and heads milled to 62cc and 1008 gasket.
 
Shoot for 10.5.1, even 10.7 would be fine with aluminum heads & that cam.
 
I think I'll aim for 10.5:1. Thanks for the
Responses.

Any recommendations on intakes?
 
Static compression will be set by the machine shop via the block and head machining. So you should be asking them or telling them what you want them to set it to. If the pistons are dished then a tight quench and small closed chamber will get you a hair over 10:1 static wich should be fine for the cam you're running. If the pistons are flat tops you need a biger cam. With what you have you should hit your mark with the EFI or a larger single 4bbl.. You may not reach it with the six pac. Those intakes are rather restrictive.
 
moper said:
Static compression will be set by the machine shop via the block and head machining. So you should be asking them or telling them what you want them to set it to. If the pistons are dished then a tight quench and small closed chamber will get you a hair over 10:1 static wich should be fine for the cam you're running. If the pistons are flat tops you need a biger cam. With what you have you should hit your mark with the EFI or a larger single 4bbl.. You may not reach it with the six pac. Those intakes are rather restrictive.
Click to expand...

Are there other heads that you can recommend for the six-pack setup incase I decide to go that route?? I haven't bought them yet. I'm just having the shortblock done right now. Thanks
 
Newf said:
Are there other heads that you can recommend for the six-pack setup incase I decide to go that route?? I haven't bought them yet. I'm just having the shortblock done right now. Thanks
Click to expand...

I would stick with your original plan. Adjusting your head choice to fit the six pack is not worth it IMO. If you choose to go 3X2 and you lose a few horsepower in the process it's not like your still not gonna have plenty. Just payin' a little price for the bling:D.
 
Any suggestions on an intake using the EFI Fast kit?
 
The six pack's problems are the intake manifold. Not the heads. Identical 416 on the dyno made 487hp with a 6bbl, mild solid roller, and stage 3 Shady Dell RPMs. With an Air Gap and HP950 it made 535. They look cool, but they really suck on a small block...lol
 
moper said:
The six pack's problems are the intake manifold. Not the heads. Identical 416 on the dyno made 487hp with a 6bbl, mild solid roller, and stage 3 Shady Dell RPMs. With an Air Gap and HP950 it made 535. They look cool, but they really suck on a small block...lol
Click to expand...

I've pretty much decided EFI, would you go dual plane Edelbrock performer? I'm not carb savvy so I probably would be constantly taking it to someone for tuning.
 
I dont see that cam listed on thier site, where can I find it , and what springs do they recommend with it ? Thanks, and good luck with your project, it sounds great.


Oops, found it , thanks
 
604B1duster said:
I dont see that cam listed on thier site, where can I find it , and what springs do they recommend with it ? Thanks, and good luck with your project, it sounds great.


Oops, found it , thanks
Click to expand...

Thanks for the encouraging words. I'll check with the machine shop on the part #'s and post them. Probably won't be till Monday though when they are open.

Cheers
 
mine works out to be 10.03 works good on 91 octaine and eldebrock heads
 
Newf said:
I've pretty much decided EFI, would you go dual plane Edelbrock performer? I'm not carb savvy so I probably would be constantly taking it to someone for tuning.
Click to expand...
Check there catalog & I think the only intake for EFI you will find is a single plane. From the little I know about EFI once the manifold no longer is used for fuel things change a bit......used to be an article here that explained why a dual plane has no advantage over a single plane, don't know if it is there anymore. If you look at some of there kits they all only mention a single plane, at least the ones I looked at. F.A.S.T. does not have any Mopar manifolds listed, but what they do have are all single planes. Pretty sure if you call/email Richard he will explain it to you.....
 
I use this calculator - you can't just guess a CR do the math, gap the rings, check your tolerances, have the rotating assembly balanced (even if it says it's balanced do it again), I'd go to a 3,000-3,500 stall converter, 3.55+ gears, 1.6 RR's will increase the cams gross lift so do the math for that also, and check PTV clearance - degree the cam

EFI= single plane carb intake- for the power you want a dual plane would hold it back...

http://www.rbracing-rsr.com/compstaticcalc.html
 
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