454/330 peanut port heads/intake MPI
 

I have a 454/330 Gen VI BBC and want to go through it and get close to 500hp. I have been researching a lot and it looks like i most likely have the peanut heads on this engine.

If i want to change to a large oval head will the current MPI intake that i have match up or will i need a different mpi intake. I know that i will need to recalibrate the mpi.

This will be a winter project and i'd like to try and develop a good plan so i can get my budget figured out!

you will need a new intake and recalibrate for the new combo

I strongly suggest you get together with the person who will re-program your ECM before making your parts selection. He will be able to reprogram your ECM for tried and true engine combinations he has worked out on an engine dyno. Follow his suggestions as far as heads and camshaft.
It is much easier for him to recalibrate your engines ECM to his combination than for him to recalibrate your engines ECM to your customized combination. Through experience, he will have a better knowledge of what works best for your engine than you will.
I also strongly suggest that you contact several different ECM programers and get multiple opinions about how to procede.
Dennis Moore

Thanks for the replies! I was hoping that that wasn't the case but i figured it would be! I have been told that i may have the 156 casting which is a smal done head and would be able to get the hp out if it with the right cam??

Thanks for the info. about the ecm! that makes sense for sure!

My goal is to get a big increase in hp but i would like to keep it reliable and on pump gas!

330
 

if you are going to make ant serious h/p you will need to do something w/the rods and pistons,crank is also cast.scat or eagle make a nice rotating assembly.you can get them in cast steel,w/4340 rods.this kit will handle 700h/p.go to the forged stuff and its good to a 1000h/p.just my 2cents,i would not even fool w/the oval port heads.for what you will pay for them,you could do square-port.the 330 is a great motor,for what it is.

I was under the impression that the 7.4L MPI engines had the larger oval Vortec heads on them, not the peanut ports.

unless you are ready to spend some serous $$$$ you might want o think about switch to a carb setup to get that power without all the issues you are going to get into to keep the EFI..

I would agree with EZSTRIPER.
Big horsepower out of a 454 is very difficult with an EFI system.
Install a GM Performance camshaft with 224/234 intake/exhaust duration w 110 LSA (part number 123665430).
An aluminum Edelbrock Performer RPM manifold and a Edelbrock 750 marine carb.
A Thunderbolt IV distributor with a 20 degree ignition advance module (V8-HP module) and you will be very happy with the performance.
Dennis Moore

Many people have been in your shoes.

"I'm on a budget and want the most performance possible while keeping everything super reliable."

Famous words !

IMHO - I believe the smartest way to do it is the following way that many people have done, but not enough. Pull that motor and put it in your garage. Great as back-up, and even better when you sell the boat. IE: with stock power. I know, I know, I'll never sell it. Yeh, right...LOL.

Then build a motor to your wants.

Doesn't sound budget friendly at first, but read the past 5-7 years (I dare you. LOL.) of this and other performance boating forums and you'll see you are standing in front of a hugely traveled path.

Above based on you wanting 500hp.

400HP with a carb, well, then you can do it to your motor on a relatively small budget and not likely to hurt anything.