Seems like I read somewhere it's best to up the compression with aluminum heads, yes or no?
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Best 454 block for rebuild and parts
- Thread starter bp71k5
- Start date
Hoss7979
1/2 ton status
You can run more compression yes....
Well, I'm not talking about the "more power" type of thing, just that I was thinking slightly more compression was needed to get the most out of the aluminum head. Not crazy compression, just that they'd be a waste on a naturally aspirated motor with 9:1 or less.
I think you could look at upping the compression even if sticking with the factory block and peanut ports. Those motors have really low compression.
https://www.summitracing.com/parts/edl-50459/overview/make/chevrolet
these are 110 cc should help bump the comp ratio a bit .
these are 110 cc should help bump the comp ratio a bit .
Hoss7979
1/2 ton status
Yep you'd wanna atleast go 9.5:1 or more. Which isn't that hard w/ closed chamber heads....
bp71k5
3/4 ton status
I've read the same thing. An iron head can make more power at same compression, so not increasing the compression would be a net loss unless upgrading pistons, etc to increase comp.
bp71k5
3/4 ton status
There's a few of these types of videos available.
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It all depends on your budget. Ultimately I just had to do a few basic mods and call it good. 230HP/380TQ is marked improvement from a worn 350 that was doing 200HP/300TQ on it's best day (and its best days were long before I owned it). I'm hoping the few mods I did at least push me up to 250/400.
Don't just bump up compression just because you're going to run aluminum heads. Decide what cam you're going to run and pick the combustion chamber and piston size to get the compression the cam wants.
bp71k5
3/4 ton status
Thanks, that's the kind of advice I need.
Hoss7979
1/2 ton status
This is pretty much what everyone has been telling you....stock BBC's unless you get the HP factory muscle ones don't have anything more than 8.5-9:1. My 468 is 9.5:1 w/ way overkill 990 heads, 2.25/1.88 ported, single plane intake, extreme 4x4 cam & 750DP. It comes in right around 505hp/570tq and revs up to 5800 easly.
Fyi, a typical stock 454 has +\-8:1 comp.
Hoss7979
1/2 ton status
But everything need is still in speculation until you really tear into it and see what the cylinder walls look like and all the bearings. But Comp Cam makes great cams for the BBC's in the form of the Extreme 4x4 flat tappet cam. Like I said I run one right now and ran one in my sbc as well. They were the second biggest one you could get. I'm switching to a Nitrous\Turbo\Blower cam this winter due to running a plate style nitrous kit now. But let use know what casting you have when ya tear it apart and we can consult after that....
the heads are off, see his build thread. https://ck5.com/forums/threads/71k5-bp71k5s-just-for-fun-build.212062/page-50
