I am currently running an LS1 with forged pistons and rods with the MS3 cam and milled 799 heads with the trunion upgrade, dual .650" springs, 7.4 PRs and LS7 lifters/trays. The injectors at 5800 rpm were at 90% and at 6200 rpm were at 99%. It put down 390hp/384tq. I have the 1 3/4 SLP full exhaust to Magnaflow CB with CME.
I am going with a VRX4 cam and wanted to know if I would have any issue with valve slap or the PRs being too big. The car revs to about 6800.

 

You'll have more clearance with the VRX4 and since it's a Comp Cam using XE-R lobes, if the pushrods were correct before, they'll still be correct, since the MS3 is an XE-R lobed Comp Cams camshaft as well.

 

Why switching the cam? I'm just curious...

 

I drive it everyday and why waste a huge cam and not even make 400 when I can make the same or a little more with a quieter cam. I also went with a 114 LSA so there is only 1* overlap aside from the 13.5* from the MS3. A friend with a c5z wants the MS3 for his build.

 

Gotcha!

 

Part of the problem is the fueling. At 99% injector duty, you run the risk of going lean, especially over 6200 RPM. I think if you fixed that you'd have more power in the MS3.

One thing the MS3 needs is a lot of compression. When I say a lot, I mean a lot. 11.8:1 at a minimum on the 113+0. But really, it needs something closer to 12.1:1. Unless you advance it 3-4 degrees. Which would work much better in a 346... with 11.8:1 CR.

 

Jake- The guy I bought the car from found all the receipts, etc. so I will go pick those up and see exactly what else he swapped.

 

Yeah, would be good to know. I'd probably replace the fuel pump and injectors once you go with heads/cam in the LS1. Stock injectors are good to about 400-420rwhp and then you need more. And the stock pump is good to maybe 450.

 

Thanks everyone! Once, I decide to go to a bigger head, I will replace injectors and fuel pump.

 

Good call. That was my thinking when I was trying to decide on a cam. Mine did 423rwhp, 386rwtq on a mustang dyno with a 228 cam.

 

Idk if I would even give them that. I've always heard that's what they're good for but my stock 28's were at 102% at 5500 rpm and I put down 380 on a mustang dyno then 420 on a dynojet before the Meziere. Now with the fast I'm doing a set of ls3's. I think I would have made more power just by swapping and tuning the injectors but we'll never know now with the intake swap.

Since you'll be getting retuned for the cam just pickup a set of ls3 injectors. I got mine for 90 bucks new take offs and with the height adapters and plug adapters I'm in the whole set for 150. They flow 42lb so will be more than enough. I maxxed out mine with bolt ons stock 243 heads and a f13 cam so you will still easily be pushing the limit of the stockers.

 

UPDATE:
I installed a VRX4 with 114 LSA. The car idles like it has a 220/220 and you can barely hear the lope, which is almost like a sleeper cam. It sounds good and it doesn't surge, even at 45 in 6th gear (4.10 gears). I also went with a 25% Powerbond UDP. Waiting for my tuner guy to get back home from LS fest.