1985 454 best heads to use?
 

hello, I'm rebuilding my 454's for my 34ft 1987 scarab. it had rectangle port heads which were corroded in the centre exhaust ports. shall i find another pair of the same heads or use oval port heads and port match the intakes to suite my manifolds. Id really like to increase the power for this rebuild and would like to know the best combo. I'll keep my rochester carbs, intake manifolds but i will get some new camshafts for them as the old ones are pitted.

rectangular

Haha!

I doubt that any change to the intake or carb only will add much to the HP and likely only 0-1 MPH on the top end.

why were they corroded in the center exhaust ports?

I think that's where the heat exchanger is so water seeps in there over time??

Yes I'll keep the carby and intake manifold same. Just like to know if I can gain more power from using the oval port heads and a particular proven camshaft ?

budget wise, something like a set of EQ's will flow better than stock and probably be a wash over finding a set of stock heads and having them redone. THe main thing it what are your plans? Is it just going to run like this or are you eventually going to want more out of it?

I don't expect too much from old technology and I want to keep it as original as possible but since I'm rebuilding the engines and have a choice of heads and cams I would like to ask opinions for best combo to increase power even if it's only small increase

profiler cnc'd,,800 lift cam,12-1 compression,,stelling long tubes 110% dry,,tunnel rams w/ efi,,lets turn those puppies up big time.:D

Is there any links on internet showing data sheets/Dyno results with that combo as a comparison to the 370 hp 454 that I had to begin with
I looked into replacing the rochesters with efi carbies and estimated the cost to be $2500 per engine so if performance increase is only slight then it's not worth it

there are 1,352,751 threads on building 454s on this site.

But you need to tell us what specifically you want to accomplish and your budget....

You could easily build a 420 clone, a 420 clone with better heads... Do you want to go with a roller cam? Do you want to spin 5000 rpm or 6200 rpm?
a basic vanilla build of a stock 454 mag bottom with budget friendly EQ heads, or a little more for Big Al's heads or a lot more for some AFRs, something somewhere between a 731/ 741/500 efi roller cam setup and valvetrain, a set of used sm's or gills could get you in the neighborhood of 450-500 hp easily but each setup would be a little different.

Correct me if I'm wrong, but EQ has a direct GM replacement head. You'll be able to use your stock valves and stuff. This is not the upgraded EQ 320 others are referring to with the better flowing ports. I belive you need different diameter and length valves for them.

Ask and you shall receive. Alittle more then 454ci though

http://i63.photobucket.com/albums/h1...B9AEBB1DC2.jpg

If u get different heads and staying 454-468 I'd look seriously at 265 cc oval port head. Intakes are cheap and you'll notice a big diff in power.

on a heavy boat with that size engines large oval ports like 781 or 049's and a performer RPM air gap intake might just be the ticket

wow ok guys, i will discuss all this info with my engine builder tomorrow and see what he says.

Yep. The EQ 320's, are basically the old RHS 320. They use an 11/32 valve like most Hi-Perf aftermarket heads. The GM heads use 3/8 valves. If he went to the EQ 320s, he needs all new hardware. IF he went with the replacement head, I believe all of his hardware can be transferred over. At least the valves. If the valves are good that is.

I also have an oval port head available :eekdrop:

http://www.ebay.com/itm/MerCruiser-5...dTjkxd&vxp=mtr

Basically, its designed to be a replacment for the GM Rect ports. The intake runner is redesigned, and smaller , at 299cc. The chamber looks to be a more modern chamber design than the GM heads.

I'd want to replace the stock exhaust manifolds with something better, and a better cam than the 370HP came with. Add some roller rockers.

Stock 400/420hp 454 cam.

http://crane.carshopinc.com/product_...d/16042/132561

Is this engine ran in saltwater?

specs and price,,thanks in advance

Thanks Rob... and for the money... properly prepped AKR/Promaxx heads will outperform the AFR heads... in dollars/performance!!!

Sutphen 30

306 CC intake runner, 2.25 SS Ferrea Intake valves, 1.900 Super Alloy Ferrea exhaust valves, Pac springs (spec'd to customer cam) hardened steel !0* locks and retainers, ARP studs and hardened 3/8" guideplates...
All my heads are spec built, not production line off the shelf product (more bang for your buck) takes a bit longer to get a lot more, but worth the painfree process

That's the oval port. I was thinking they were 290 cc. Then again I thought the smaller rectangular ports were 320 but they are 317. Regardless what great heads and I hope they really take off.

290 edelbrock heads (Marine if kept in salt water), Torker II intake (even with just a 315 HP cam is a big jump like adding 75 100 something NOS) Magnum cam even better and go with the newer Magnum firing order. Notch the bores for intake valve clearance. 850 Quick Fuel marine carb. Figure in different props too

I never stated what they started life as getrdunn... and thank you so do we hope they really take off!!!

salt yes

casting 049 large oval port heads. Will make more torque down low, good to 6000rpm if massaged a little. will need to have hardened seat put in for unleaded fuel, and of course, change intakes. Best high torque old school head around, IMHO.

A block that age I would make sure to have it mag'd and sonic tested. You may also find yourself needing to helicoil all of the head bolt boss'es. Might be better off buying a 454HO or 502HO long block.

i got rid of the block and heads as the threads were eaten and the ports were corroded
i found x2 automotive blocks and automotive rectangular port heads.
we have ordered x2 new cams, springs to match and some new lifters.
short motors are ready
now we want to make sure the manifold, the heads and the carby will give it plenty of power so thinking about it. should we use the existing manifolds and put a spacer under the carby to increase the air speed or just get x2 new bigger manifolds. also the carbies are rochesters and we want to make sure they are sufficient. compression ratio to match 98 octane bowser fuel. stuff like that.