mark IV 454 1983

[craig akiyama]

I need some input on a build i'm doing 454 short deck open chamber, It looks like it's pretty affordable to get like a eagle stroker kit, simi dome pistons, It must pass ca. smog. so like a voodoo flat tappet cam with a rv grind, mabey a swap meet aluminum intake dule plane mamifold to fit a 850 cfm Holly, My qustion will this make good low-mid power with stock oval heads that have been port matched and polished by me,new heads are way out of my budget. I would try to buy stainless swerl polished valves stock, and and new springs

[Geezer2]

For the dough, I'd buy the kit from SCAT..same $$$$$$$ better quality machine work.

I've used their cast steel cranks in engines up to 750 HP with no problems.

The oval port heads will make all the power you're after with no problem.

[skids72]

I need some input on a build i'm doing 454 short deck open chamber, It looks like it's pretty affordable to get like a eagle stroker kit, simi dome pistons, It must pass ca. smog. so like a voodoo flat tappet cam with a rv grind, mabey a swap meet aluminum intake dule plane mamifold to fit a 850 cfm Holly, My qustion will this make good low-mid power with stock oval heads that have been port matched and polished by me,new heads are way out of my budget. I would try to buy stainless swerl polished valves stock, and and new springs

Heads should be plenty stout for low/mid range... I would think about a 750cfm vac secondary for better throttle response unless you'll be spending time over 6000rpm. I think the 850 carb will be a little lazy for a low end tq build.

Two cents,

-Chris

[35WINDOW]

It really depends on which Oval Ports you use-hopefully you have some 049's or 781's-hopefully you don't have the "peanut port" truck heads-

[craig akiyama]

the only information i can find is cast no.346236 made in 1981 open port 113.0cc chamber oval port.

[35WINDOW]

From the Mortec site..

346236.....454.......75-76...2-bolt

What is he casting on your Heads-I believe you are giving us your Block Casting #'s

[craig akiyama]

these are on the head runners top k 24-81 and 346236 i just dubble checked

[MAW]

Those heads should be '75-'87 oval port open 120cc chambers, 225/116 ports.

Cheers, Mark

[35WINDOW]

Well,

I went searching and found this on a Camaro site-

346236 1975-87 454 Open 113.0cc

2.06" Intake, 1.72" Exhaust

And, I found this on Roadsters.com:

346236 454 1975-1978 Open chamber ("peanut" ports)

Looks like they are not the best for performance-I'd see if I could find some 049's or 781's-

[craig akiyama]

are they bad for the runner size or because it's such a long runner or chamber shape under the valve.

[65cayne]

I need some input on a build i'm doing 454 short deck open chamber, It looks like it's pretty affordable to get like a eagle stroker kit, simi dome pistons, It must pass ca. smog. so like a voodoo flat tappet cam with a rv grind, mabey a swap meet aluminum intake dule plane mamifold to fit a 850 cfm Holly, My qustion will this make good low-mid power with stock oval heads that have been port matched and polished by me,new heads are way out of my budget. I would try to buy stainless swerl polished valves stock, and and new springs

If you stayed with the 454, yes those 236 will make excellent LOW and MID range torque with a mild cam like that. Top end power does get soft rather quick when you approach and cross the 5000rpm mark. For a purely street car, I dont see this as a problem. This is basically what I am running with 3.36 gears, 9.3CR, and the Voodoo 60201 (basically your "RV cam"). If you want to keep a small budget, that's the way to go.

Many people will tell you different. I am here to tell you that they are playing on a different level. With the 236's you would still have plenty of power for the street with the right gears.

However, yes, even I would NOT recommend those heads for a 496cid.

Do you plan on running street friendly gears? Auto or Stick?

[craig akiyama]

it's a dully with a thm400 and i'd plan on a gear vendors overdrive. I read a guy who said they make good door stops, but I also heard IF you can find 049's or 781's and rebuild them you'd just about have a set of aluminum for almost the same amount of money (what size carb are you running)

[pat mccarthy]

WHO told you all what

[65cayne]

...I read a guy who said they make good door stops...(what size carb are you running)

Yes, a lot of people will tell you that.


I am running a holley 770SA vacuum secondary.

[pat mccarthy]

Yes, a lot of people will tell you that.

and alot of people do not know nothing like i told you them heads make 330 hp on a boat in stock form for low rpm or a small cid big block i would use them in a low buck build sounds like with a over drive you not going to see hi rpm so how big of a head do you need if you never going past 4500