embs2001

Im wondering if it is worth it to move the stock shift points from 5500 up to 5800-6000? Its a stock cam LM7 with 9psi boost, Longtubes, true dual exhaust, 90mm throttle body, Drop in K&N filter, 2800 stall, And 3.73 gears. RCSB 4x4. Not expecting more power from it, just quicker with less rpm droo.

Thanks, Let me know what you think!

03sierraslt

iTrader: (22)

You could but be aware of valve float, stock springs are pretty weak. I would say closer to 5800

2 SSlow

iTrader: (25)

Throw some LS9 valve springs in there for $57 and let'er eat.

embs2001

Thanks guys.
I have some yellow ls6 springs I got for free, just too lazy to put them in. I imagine the stock cam doesnt have much to offer past 5800 anyway?

Vortec350ss

iTrader: (20)

Yea I wouldn't bother going past 5800. 5800 and 10psi would feel strong. As you push the boost higher your cam will start to fall off even earlier. I would definitely upgrade those springs...
The more boost you make the less your shift extensions will be of concern. It will pull hard in the mid range. Out of curiosity what pulley are you running to make 9PSI?

embs2001

This is a lsa blower with the stock 2.95 pulley. Its usually around 8psi in the lower rpms and climbs to 9 in upper. not sure why its like that but I suppose its because the blower is spinning slower than it did on a LSA stock?

Vortec350ss

iTrader: (20)

Yes the LSA has a larger crank pulley than you do. Thats still a fairly small pulley to only make 9PSI on your engine.

embs2001

4 or 5 other people on the forums with the same blower on a 5.3 said they had 8.5-9 lbs with the stock pulley. The guy who sold me the adapter plates and fuel rail said everyone is seeing the same 8-9 with the stock pulley.

What would you expect from a maggie 1900 with same lower and upper pulleys?

Vortec350ss

iTrader: (20)

I guess Id have expected north of 10 for sure. Between the stock cam and smaller cubes. I made 10 with the stock crank pulley and a 2.7 upper. But 6.0 vs 5.3 and cam vs no cam...

embs2001

Yea it is weird. Something must be diffrent between the maggie 1900 and LSA 1900.