What Thorley headers are you talking about?? Are they long tubes or shorties? I'm looking at putting some headers on mine but am not sure about the complications of the LT's especially with as much mud and snow as we have. Wondering if Edelbrock (or whatever) shorties are worth any power gain, especially with towing?

 

i was going to use the long tube headers, if i am going to bash my fingers with rusty exhaust bolts i want it to be worth it. the thorley headers should hold up they have the thickest gauge tubeing and flanges of all the brands i looked at. i really do not want to be changeing gaskets every oil change.

 

i am looking more for hp the fuel mileage would be a nice plus. makes it easy to justify the money spent

 

How much?? Do you have to mess with the o2 and all that lovely stuff?? I suppose you have to get all new crossovers and such? Not sure I want that much work.....although.....horsepower is a beautiful thing!

 

Comp cams makes 2 springs for the LS1 that are bolt on for the Vortec iron heads, they are Beehive type and allow for valve lift of .550 on the Vortecs. FINALLY I can get a nice cam for my Vortec 350.

To use teh 1.6:1 rockers on teh vortec head, you will need to elongate the push rod hole ever so slightly with a 2/8" drill bit, the larger ratio rocker arms move the pushrod closer to the rocker trunnion and the push rod will rub on the head at the push rod hole.

peace
Hog

 

Here is a list of most of the GM cams that will work in your truck.
LT1 1.5 ratio .447/.459 201/208 ??? 95-97 fbody Lt1 alum. head 10.5:1 170cc
LT4 1.6 ratio .476/.480 203/210 115 alum LT4 head 10.8:1 195cc 6300rpm redline in LT4
LT4 1.5 ratio .446/.450 203/210 115 alum LT4 head 10.8:1 1.5's reduce a little duration
L31 1.5 ratio .414/.429 192/197 ??? iron head 9.4:1 170cc
L31 1.6 ratio .444/.459 192/197 ??? 1.6's add a little duration 170cc
L98 1.5 .403/.415 202/206 115 245 hp 4200 330@3200 sae net
Hot 1.6 ratio .525/.525 218/228 112 LT4 or Fastburn alum. 430hp@6000 ZZ430
Hot 1.5 ratio .495/.495 218/228 112 1.5's reduce duration a little
350 1.5 .474/.510 208/221 112 ZZ4 cam 355hp@5250 405@3500 with alum L98
400hp@5500 400@4500 with Fastburn alum
350 HO 1.5 .488/.509 214/218 112
383HT&RJ350 .431/.451 196/206 109 HT 383/340hp@4500 435@4000 vortec iron heads
383ZZ 1.5 .509/.528 222/230 112 GM 425hp@5400 460@4500 ZZ383 camFBalumhead
????? 1.5 .539/.558 234/242 112 ???in GM perf. parts book, along with all other cams

Well these are pretty much all of the GM made roller cams for possible use in any GEN I (TBI, TPI, VORTEC)and GEN II (LT1, LT4)smallblock originally equiped with a roller cam.

There are LOTS of aftermarket cams for the 96-99 Vortec 305's and 350's, just look for cams for 1993-1997 LT1 Camaros/FireBird and 1992-1996 LT1 and LT4 Corvettes, or the 1988 and up Camaros/Firebirds/Vettes with TPI/TBI with rollercams.

I just read a test that used the GM LT4 Hotcam and it made 403 hp on a stock Vortec headed engine with a carb. The Hotcam has 218/228 duration and .525/.525 lift with 1.6:1 rockers. Or .492/.492 lift with 1/5:1 rockers.


Which heads do you have, either the Fastburn heads with 210cc intake ports or the ZZ4 heads which are L98 aluminum heads, in your signature you say Fastburn ZZ4 heads, this is confusing.
Lingenfelter also makes a bunch of cool cams, their 213/219 .493/502 cam looks cool. You can get this cam for $75.00US brand new off of ebay directly from Lingenfelter engineering. http://www.lingenfelter.com/store/c30.html

If you go with a 383 with your current combo, you will run out of injector for sure. You state that you are dynoing at 304 rwhp, the most hp I have seen on a L31 Vortec 350 stock injection is 330 rwhp which is 397 at the crank. Anyt thing over 400 crank or 330 rwhp is impossible due to the stock 19 lb/hr poppet injectors.

Also remember that no one has been able to rev a 1996-99 L31/L30 V8 over 5800 rpm due to the inability of Pro PCM tuners to set the rev limit over 5800 rpm The injector pulsewidth just goes to zero at 5800 until the revs come down a bit.

I run the Hookers long tube Competition Series coated headers, they have 1 5/8" primaries and 2 1/2" colectors and have lasted me 5 years with daily driving Canadian Winters in the salt. m Summit sells them for $359.00US.

Thorleys are more of a mid length header with custom crossover pipes to the cats, the long tube Hookers required me to run custom crossovers which I made of 2/5:" stainless, teh stock headpipes are 1 7/8" and have bad crimps on both sides, custom headpipes will give you much better flow.

the S10 L35 V6 is also a nice addition for not much money.

peace
Hog

 

you can try a msd 6al box and coil and good plug wires

 

did you notice any power gains with the msd box. i used on on my 67 pontiac and it made a big diff but i never used one on a fuel injected motor. also speaking of ignition is the ac delco cap and rotor the best set up or is there a better way to go

 

i think the acdelco cap and rotor should fine really no diff as far as cap and rotors go except the brass terminal caps are a little better..........it was so long ago on the msd box i cant remember i had it on my 91 ecsb 350 i believe it gave a little better fuel economy and throttle response

 

i amgoing to pull the msd box off of my pontiac and try it for a while since i cant drive that car this time of year.thanks for the idea.