Peanut 454 upgrades

[be1464]

During the off season I’m thinking about swapping out my peanut heads for a set of magnum heads. I’ve already got lightning headers but I’m also going to add the intake manifold to match the square ports and slap a bigger carb on there. I’m wanting to know if anyone on here has had experience with doing this exact upgrade. If so I’d like to know the gains you got and if it still maintained the stock reliability. Thanks

 

[DarkHorseRacing]

You didnt say what this was going to be used in. There's a decent article on doing some cleanup on a peanut head 454 with a few little changes that can bring some additional power to the peanut port 454:

Power For Peanuts: Gen V Big Block Power

By Richard Holdener/Photos by Author We all love big-block Chevys, right? But does that love affair include the much –maligned, peanut-port motors? For the uninitiated, peanut port refers to the small, oval-port heads used on the Gen-V 454 truck motors run prior to the introduction of the Gen...

www.cpgnation.com

You wouldnt even have to swap the heads if this was along the lines of your expectations.

Obviously rectangular port heads have more flow and generate more power but they also change the powerband and where the HP and TQ curves peak, which might not be desired.

 

[be1464]

I’ll be doing this to my 96 Nordic scandia

 

[obnoxious001]

During the off season I’m thinking about swapping out my peanut heads for a set of magnum heads. I’ve already got lightning headers but I’m also going to add the intake manifold to match the square ports and slap a bigger carb on there. I’m wanting to know if anyone on here has had experience with doing this exact upgrade. If so I’d like to know the gains you got and if it still maintained the stock reliability. Thanks

Some questions that will help in deciding if rectangular ports are in your best interest.

What's your max RPM with the current setup? What are you hoping to improve, only top end performance?

What size carb do you currently have?

Reliability should not change at all if the replacement heads are properly installed, with spring pressures that match your cam.

Bigger carb may not help at all, depending on what you currently have and what max RPM you are able to run. Close friend of mine thought he would improve performance on his jet boat by a carb change. I had assembled a very mild engine for him with larger oval port heads and a jet boat cam. So he goes out and buys an 850 Demon carb without checking with me to replace his original 715 CFM Holley (yes, 715). It actually took quite a bit of work on the new carb to get the engine to run as well as it did with the smaller carb, and it never did run any better as much as we tuned on it. His 454 engine could only use so much air and fuel at 5200 RPM, where the impeller let it run.

You don't even have the benefit of an upgraded camshaft, correct?

 

[be1464]

Some questions that will help in deciding if rectangular ports are in your best interest.

What's your max RPM with the current setup? What are you hoping to improve, only top end performance?

What size carb do you currently have?

Reliability should not change at all if the replacement heads are properly installed, with spring pressures that match your cam.

Bigger carb may not help at all, depending on what you currently have and what max RPM you are able to run. Close friend of mine thought he would improve performance on his jet boat by a carb change. I had assembled a very mild engine for him with larger oval port heads and a jet boat cam. So he goes out and buys an 850 Demon carb without checking with me to replace his original 715 CFM Holley (yes, 715). It actually took quite a bit of work on the new carb to get the engine to run as well as it did with the smaller carb, and it never did run any better as much as we tuned on it. His 454 engine could only use so much air and fuel at 5200 RPM, where the impeller let it run.

You don't even have the benefit of an upgraded camshaft, correct?

I’ve got a stock 7.4 with lightnings that’s it. But I’d like to gain power power through the curve. Currently I’m topping out at 4800 rpm with a b1 22p 4 blade at 55 mph. It’s got the stock quadrajet I believe

 

[obnoxious001]

I’ve got a stock 7.4 with lightnings that’s it. But I’d like to gain power power through the curve. Currently I’m topping out at 4800 rpm with a b1 22p 4 blade at 55 mph. It’s got the stock quadrajet I believe

You would be better off looking for large oval port heads, since you won't increase RPM level enough with mild changes to make use of where the rectangular ports are designed to make power. See if any of the Brodix Race Rite oval port heads are available (they've been very hard to get). More camshaft will help, but it takes a lot of work to change one out with the engine in the boat, however for the engine to make better power you need to make all the components work together.

 

[be1464]

You would be better off looking for large oval port heads, since you won't increase RPM level enough with mild changes to make use of where the rectangular ports are designed to make power. See if any of the Brodix Race Rite oval port heads are available (they've been very hard to get). More camshaft will help, but it takes a lot of work to change one out with the engine in the boat, however for the engine to make better power you need to make all the components work together.

Gotcha I appreciate the help

 

[obnoxious001]

Gotcha I appreciate the help

I have built a lot of marine engines, if you go back on RDP a few years you will find some write ups I did on some builds. I tend not to do that anymore, it adds a bunch more time having to clean up to be able to handle the camera in between steps.

Other thing you may want to consider is a leak down check of the engine to see how fresh or tired it may be.