blazeracer said:
Thanks guys. Scored the power plant today. No junk yard dawg this time. This is an all aluminum true LS1 with CNC ported AFR heads pullled from a Vette with 67k on the clock that chassis dyno'd 440hp at the tires. Proven engine ready for action.
Gonna sell the EFI sh!t and run a carb on this one.
Very cool. Some words of advice, but you can ignore them if you want.
1) The aluminum block engines need to run at least 160*, and ideally in the 180* range. Any less and they are losing power - and potentially longevity.
2) With the tunnel hull, you will likely need to run a remote oil filter - and possibly a top mount starter. You'll find out soon enough, but do look for clearance in those areas.
3) I'd very much recommend a rod bolt upgrade. You're getting up there in horsepower, and probably in revs. Cheap insurance.
4) Get a single plane manifold. I'd skip the Performer RPM and Victor Jr. Look at a Super Vic or GMPP manifold.
5) Whether you run open or closed cooling, I'd make sure to run at least 1 coolant crossover, if not 2. It helps eliminate hot spots in the top of the heads.
6) With the higher compression of the LS1, I'd limit max timing to 28-29* total. Being AFR heads, 29* will probably be spot on. You probably won't see any gains above that anyways...but you could (VERY likely) have some detonation issues with 30*+. The timing curve should be something like 14* from 0-1500 rpm, then ramping to 25* at about 2200-2500 rpm, then ramping to 29* at 3000-3200 rpm where it stays until the rev limit. You *might* need to back it off to 28* at about 5200+ rpm.
7) LS engines for some reason love big carbs. It doesn't make sense...but something in the 800-850 range is probably what you want. I tried a 700, 750, 800, and 850 cfm on mine. It liked the 850 the best. I never tried a bigger carb than 850 cfm.
8) My testing has shown that tunnels really like back cut shoes. Even with the lighter weight of the aluminum engine, my boat runs very well with a 2* back cut. I'd limit mouth opening to somewhere around 14".
9) You might also look at the trunion upgrade for the rockers. With sustained high rpm it would be cheap insurance.
As for carb vs EFI. I can guarantee that you will make more power above 5300 rpm with a Super Vic than you will a Fast 90/90 combo. You will lose some driveability and the super easy start, but will definitely gain power if jetted correctly. In some ways, I have regretted going EFI - and that's why I will be trying 2 new EFI manifolds when summer gets here.
** Incidentally - I might sell my Super Victor, MSD 6010, and Demon 850. Not sure...but if you're interested, let me know. I am also going to try my HTP straight snoot back to back this summer against my droop. If it doesn't help, it'll be for sale. It's powdercoated black.
