how's this combo sound for 440 RWHP?

Figured I'd make a compromise since I have a big cube gen 1 stroker I'm trying to finish as well as a ton of other things in my life I'm trying to take care of. Gotta love the family life ;)

I have a lifter tick and a bad pilot bearing in my '98 C5 so I decided when I get back from deployment, my motor will come out. Since I have a relatively new '98 LS1 SS engine I figured I'd take it and do the following:

stock bottom end with ARP rod bolts and main studs
modified LS6 oil pump
ARP head bolts
MLS head gaskets
PRC LS6 heads and 918 springs
reuse 226/230/114 comp cam and pushrods
new lifters
rollmaster LS1 double roller timing chain
LS6 intake
ported stock TB
flowmatched 30# SVO injectors
racetronix C5 fuel pump kit

Car already has longtubes and catback, u/d pulleys, MAF ends and cold air intake. Figured I could drive on the same dynotune until I can get it updated, then swap the injectors. I originally wanted a bigger motor but with a house on the way I think I need to make a compromise. I figured it would be good for between 430 and 440 RWHP in a C5 M6, and considering the parts I already have, I should be able to do this for around $2200 in parts. Does this combo seem sound? The engine only has 320 miles on it and I plan on using whatever sensors I can since they are all new GM.

I'd say that combo would make in the mid to high 420 whp range tops.

I'd say that combo would make in the mid to high 420 whp range tops.

id agree with that

Needs more cam. :)

What stage PRC heads?

I think it will hit your 430-440whp mark. How much lift with your cam and what will your SCR be?

Even on the ls1tech threads where TSP is bragging about their heads, the 224-228 duration cams aren't getting 430-440whp. The mid 230 grind cams are and thats also in M6 f-bodies. A C5 will dyno a little lower due to the IRS. I'm not saying it won't be a strong set up, just not peek like a larger cam. You'll probably be happier with the power under the curve than you would with a larger cam too.


My question is, what does the car make now?

Try a Futral Motorsports F13 or F14 camshaft along with those heads and you'll be over your mark. The cam you currently have is a pussy cam :lol:

Also, there's no need to change the fuel pump. The stock one can handle upwards of 550rwhp. I'm still using the stocker.

If you're going to be in the bottom end, why not upgrade the crank to a forged piece? Just out of curiosity.

What's the lift on the cam? I take it you want something streetable, hence the 114 LSA.

If I went forged, I might as well just step up to a 402 stroker. I have a practically brand new LS1 in the garage and figure I might as well use it.

Not looking for max power out of this one. I want a compromise of streetability, dependability and affordability. I have my Camaro to toy with and a motor for it I'm still trying to finish up.

Not looking for anything larger in the cam really. Like I said, it gets great mileage and is a driver.

Car makes 354RWHP on a stock bottom end, stock heads and LS1 intake. It's only got a cam, 918's and pushrods, longtubes and exhaust, pulleys, maf ends, cold air intake, and tuning for the most part.

Pump is original and even though it's fine, I want to upgrade it now instead of worrying about it later, having it just quit on me. I need to depend on this one.

I don't think that you will hit the 440 mark without really pushing the tune. I would upgrade the fuel system as you have said. My fuel pump was done after a month on the stock injectors. The only thing that I would suggest is to switch the stock pistons for some forged. Ring lands on the stock are pretty weak once you up the power.

Kraest: How is your mileage with your 408? I was considering building a 402 if I could source an aluminum 4" bore block, and if I change pistons and rods, I might as well change the crank too. I just dont want to take too much of a hit. I get 33mpg on the highway right now and would like to stay at or over 30 since it's my driver.

Dont see too many nassau blue metallic owners around :D

Kraest: How is your mileage with your 408? I was considering building a 402 if I could source an aluminum 4" bore block, and if I change pistons and rods, I might as well change the crank too. I just dont want to take too much of a hit. I get 33mpg on the highway right now and would like to stay at or over 30 since it's my driver.

Dont see too many nassau blue metallic owners around :D

Nah, you don't get 33 mpg. That's what the digital read-out says, but that's not accurate if you are using anything but stock injectors. My car says it gets 40 mpg at 1600 rpm at 80mph, but looking at the mileage it gets more like 22-25 mpg tops.

That wasnt 33mpg using the DIC, it was 33mpg doing the math. I went 550 miles from Tallahassee FL to Fayetteville NC, and the reserve fuel warning on the DIC came on right before getting there so I still had a little fuel in the tank.

Dont wanna mess the mileage up too bad. And yes I do have stock injectors. When I put on the heads and other upgrades, I'm stepping up to 30's mostly because they will be new and flowmatched, and they'll give me just a touch more fuel.

If you're going to be in the bottom end, why not upgrade the crank to a forged piece? Just out of curiosity.



Why, this isn't an LT1 or SBC. The stock LS1 crank is good for 7-8-900hp. Heck Matt Harlan was making over 1000 rwhp on his twin turbo Firehawk with the stock crank in it.

Since I'm gonna be buying both heads and intake, I'd rather spend the same or less money and get the L92 heads and L76 intake... But I dont have a 4" bore block or rotating assembly. If I built it that way, I'd rather build it as a 6.0 to help out with mileage since I'd hate to go bigger with a bigger cam and lower the mileage... but then I would have to worry about the size of the heads and intake's port velocity making it a dog. *sigh*

Too bad I cant just put in smaller intake valves and use them on an LS1. I'd drop all my coin into a 402, but I already have a 434 sbc I'm trying to finish up. And my heads gotta come off anyway because of the lifter tick. :(