Aluminium heads on Mercruiser 454

[Cdog]

Im curious, what kind of HP & TQ increase would one expect with a pair of bang for the buck aluminium heads on a carbed merc 454? The engine has rectangular port heads on it already with roller rockers. This is the 365 hp rated engine. 8.5 compression I believe. Is it worth messing with?

Thx!

 

[rivrrts429]

What boat? Typically heads are apart of a bigger equation factoring in cam, intake, and carb choice.

If you’re going to go that deep I’d build a package around the entire upper end.

Heads alone you’ll shave weight but depending on the boat you’re not likely to see a difference. Even less if you’re shopping with a tight budget.

 

[Cdog]

What boat? Typically heads are apart of a bigger equation factoring in cam, intake, and carb choice.

If you’re going to go that deep I’d build a package around the entire upper end.

Heads alone you’ll shave weight but depending on the boat you’re not likely to see a difference. Even less if you’re shopping with a tight budget.

21 HOWARD RC B1 I/O. I’ve been doing bolt ons to it and having some fun with it.

I bought the boat from a widow so I don’t have much history on it.

It only has 160 hours on it and I suspect it has an old b&m blower cam in it from the cam card I found with the paperwork. The dual plane intake has rtv as a gasket between the intake & block so I’m guessing it’s been off for the cam install.

I should probably just leave it but you know how us gear heads are lol!!

 

[02HoWaRd26]

With a blower cam be cool to do a set of Edelbrock heads and a little B&M or 8/71 with low boost would look bad ass and be good for an easy 100-125hp with minimal boost

 

[wzuber]

the blower cam timing isn't helping your n/a application, spending less or same $ on a hi quality port job on your existing heads will give you more benefits. at your operational rpm I believe a set of oval ports would yield better port flow velocity and cylinder filing and power. jmo

 

[whipple charged]

I have these ones for sale..

https://www.riverdavesplace.com/forums/threads/dart-bbc-heads.184908/

 

[Cdog]

I have these ones for sale..

https://www.riverdavesplace.com/forums/threads/dart-bbc-heads.184908/

Wish I could but out of my budget for now. Cheers!

 

[racerden]

Historically if you are going from closed chambers you'll loose some compression due to the open chamber configuration and gain power on the big end. But that's just a simple equation from experience on a NA engine. Like the others say, there's a ton more to factor in.

 

[Cdog]

I picked up a pro charger and a ASM/Pfaff intake to run on the engine. Looks like I’m gonna stick with these. Port match, clean up, arp head studs and run them.