boatlessatm

GrannySShifting

Yes they are about 90# heavier not a big deal.

If you have a 408 LS you can accidentally make 600hp, we regularly make over 500 to the rear tires in cars every day in the shop

At the engine they will make 530-570 ft lb depending on combo and power will depend on how long you can carry that out with headflow and cam timing. Weve made nearer to 700flywheel with stuff that gets driven on the street

How much camshaft in yours Corey and hows the exhaust setup/reversion? Thats what Ive wondered about how much you can get away with there. Done custom LSx cams for 15 years, but not with so restrictive exhausts on them

Wildman_grafix

Hey man I don't want to derail your thread but what block are you guys starting with? Is the LSA 427 easy to come by?

Also, looked at some programmers, have you kept the VCT when you modify? Seems one nice thing about the stock computers is cheap and a ton of capability. I am not worried about reversion, no noise laws, I run dry so I don't need to worry.

corey331

My cam is 243/250, .621/.613 112lsa, and it reverted like CRAZY!!! Even with the water entering the exhaust 1/4" from the end of the tip it reverted. I had to make the exhaust completely dry. It sounds like it should be a lot faster than it actually is now, lol. That cam was spec'd according to the flow numbers that PRC gave me on the port job that was done. I'm guessing that either their numbers weren't right, or that the heads hadn't been ported as extensively as they thought, cause on the dyno you could see how the heads were choking the motor. Also, I didn't want to push it so the tune is really conservative, I think my max timing is set at 27*. I wanted something turn key that I wasn't going to constantly be messing with. It runs good, but I know there is a lot more in it with just a head swap, so that'll happen after this season.

This video was taken last weekend when I de-winterized it. You can see what I mean about the damn thing being loud!!!

corey331

So far I have seen a best of 75mph on GPS at 5600-5700rpms, but I still have a lot of playing with props to do. I want to get it where the rpms are up to 6000-6200 at full throttle. When I get it up there I think I should be in the upper 70's. After the head swap, I would like to see over 80mph. As far as acceleration, the thing actually pulls really hard once you get it spinning and trimmed up. From 3500rpm to 5600 or so is a blast!!! On plane time is actually better than with the big block that was in it. I attribute most of that to the weight savings.

GrannySShifting

Thats actually a good bit of timing Corey, on our NA stuff Ive NEVER had to run more than 27-28 degrees to make max power. Im assuming you run it on 93?

PRC heads have never had any consistancy to them, I used to use them with some pretty good results when i first opened up shop on my own in 03-04ish, but every once in a while Id get one same combo but was a bit of a dud so I got away from using them. QC department was always lacking a bit

Thats a pretty typical average street car cam, I definitely would think that wouldnt pan out well in a boat app unless you had some reallly nice headers

No wirries on thread derail, thats what its here for. Never understood why these motors didnt get used more. The LSA is a 6.2 not a 7.0 (427) its the supercharged CTSV/ZL1 engine. Blocks are not easy to come by but not really necessary. Im using 6.0 motors, weve made 1000-1250hp on stock ones in the cars, but Im pretty good at tuning them. Stock ECUs for me, yes if you use the drive by wire ECUs you can retain the variable cam stuff etc. Mine will be setup flex fuel capable so it can be filled up at any marina, but if I want to make some steam I can load it up with e85 from the gas pump for a poker run or something

Wildman_grafix

That is not loud,,,,,,,, sounds good. Lighting headers?

corey331