96FastSilvy

ok im gonna ask some questions about a L31 build. i cant afford a 5.3 swap like i want so im sticking to this.

LT4 Hotcam
1.6 RR
Long tube Headers
3:90's
3000 stall
nitrous

how well will this combo work in a L31?

mds2004

I dont think they make 3.90s for the 10 bolt rear so maybe 4.10 gears. Put in a nice Limited slip too. It seems most go with the Eaton. I like my Auburn ECTED but its for different reasons.

Imo that cam is way too large for the motor. Without switching to the Van PCM you cannot rev above 5800. Another truck in my town runs that cam in his 383 in his ECSB and thinks its still somewhat big.

You can save money with getting a higher lift camp instead of 1.6 RR. Also make sure you machine the heads if going with high lift. I do not remember what your cams exact specs are but even with my cam I had to have the heads machined.

A Low Dime

iTrader: (13)

You can swap on the Marine L31 intake manifold to solve any and all of your fueling issues.
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GMCtrk

iTrader: (27)

Yukon makes 3.90s

mds2004

Yeah the marine intake will fix all of your fueling issues buy letting you get rid of the spider assembly and using interchangeable injectors by going mpfi.

A huge problem still is your revs being limited at 5800.

All in all, I wish I converted to a 6.0L.

96FastSilvy

whats a good cam where i wont have to have my heads machined but will sound lopy? also that will give power under 5800rpm? also that i can use stock rockers or 1.6RR

mds2004

You can use stock rockers just fine, but if you wanted to all the power you can get you can go with full rollers. I think the max lift with the heads is .480 and with +.050 locks and retainers then that bumps it to .530 so look for a cam with a max lift a little below .530.

Even a small cam without lope will take advantage of the power all the way to the 5800 so if you want a cam for sound you can definitely go big but your power will just come on much later. It is a give and take situation depending on if you want more useable power or a more aggressive lopey sound.

On our 383s, I use the 218/224 113LSA and you really have to know the engine to know if it has a cam. Ive had a few people ask but most people wont know. On the other truck locally, the LT4 hotcam 218/228 112LSA loped pretty damned hard. I believe the general rule of thumb between 350 and 383 is 10 so think 208/218 112LSA to lope hard. Someone correct me if Im wrong as I am speaking of hearsay and do not really have much experience with the L31 as a 350.

hog

Hotcam on a Vortec 350 with ported Vortec heads will net about 300 rwhp, on a 383 about 335rwhp.
Vortec Stroker has his ecab shortbox 2wd running 13.7's with his ported Vortec headed 383, STOCK L31 intake manifold and poppets, VMax intake manifold spacer(not a t-body spacer), LT headers, with a Vigilante 3000rpm stall.
He runs a Fastchip(Ed Wright) PCM tune, as do I.(modified slightly with Tunercats2) and he still has soem fueling room.
He said that the Hotcam in a 383 Vortec was too much, and needed the Vig to get any driveability, he likes his 383 combo now.
Pretty amazing numbers for the stock 19 lb/hr poppets, on the older GEN 1e intake.

the 411 PCM swap using the 2001-2002 Express van calibration is a very easy swap. Allows for EFILive-HPTuners tuning as they dont support the 96-97 trucks plus no more 5800 rpm hardlimit.

I also run the marine intake.

peace
Hog

mds2004

Yeah Hog, pauly, whatever your name is seems to be one of the most knowledgeable with our motors.

And Vortec Stroker who he mentioned above is the person who Ive met in town.