rik89gta

Hello fellow gearheads,

I plan on installing a Vortec headed, forged roller 383 with an HSR intake, Hedman shorties with Y pipe, LT4 Hotcam, roller rockers, 30 lb injectors, and later on I'll try one of those Summit 58mm tb's. The shortblock I'm looking at is listed on e bay motors and with my 64 cc chambers, I will probably order a setup with dished pistons that will put my CR in the 9.7 to 1 range. I know I'm being a little conservative with my parts selection.... But I've heard of a few guys running well over 375 hp with 350's and tpi style setups. Any input would be greatly appreciated!

norcalz28

iTrader: (13)

Yeah you should be able to get there no problem. I know people making close to that with significantly less potent parts.

Will

rik89gta

Anybody else have any thoughts on what I can expect from this combo?

1989GTATransAm

iTrader: (3)

It's all in the build and doing the little things. You have to check everything. Just because the pistons and heads are advertised at a certain cc that does not mean your heads are. Yes you should be able to do it.

89Nighthawk

I don't think you'll get 375 rwhp, at the crank, yes. I'd figure it out on DYNOSim but I don't know the LT4 Hot Cam specs.

rik89gta

IIRC...The cam specs are 218 and 224 @ 0.50. And .510, .525 lift. I'm not too positive if this is the cam I want to choose, but I need something that won't surpass my .550 spring capability that are installed on my heads. I need something that can be easily tuned while making great power.

89Nighthawk

Where are you getting your heads from and any mods?

rik89gta

I've already got the Vortec Heads with SDPC springs that are capable of .550 lift. They are slightly used but I got a great deal on them. I hear they flow well enough to make power up to 6k rpm's with the right cam.

88BlackZ-51

iTrader: (2)

I dont think you will get 375 rwhp with those mods. The C/R is somewhat weak, and if I remember correctly those heads have 1.94 valves and dont flow that well.

customblackbird

iTrader: (15)

u wont get 375rwhp with that combo, i was looking at the same thing but the cam and heads are killing u, the 170cc vortechs flow great out of the box but arent enought for that air hungry 383, on a 350 the vortechs could make 400hp at the crank mabye. a 350 tpi with vortech heads,GM hot cam, highflow SDPC base, highflow runners, injectors, TB, porting etc and it only made 355hp and 423 torque at the crank, inorder for u to get 375 rwhp you would have to be putting out probably 450-475 at the crank, your 383's gona need larger heads, a more aggressive cam and at least 30lb injectors with the HSR. and a 58mm TB.

the hot cam specs are 218 228 and .525 .525 with 1.6 rockers
ive seen vortech headed and hot cam'd 383's with carbs make 423hp, u should be looking into 190cc heads or more and give comp cams a call

rik89gta

Dang! I thought the Vortec heads flowed extremely well while making great power up to 6,000 rpm's. Any suggestions on a good cam and torque converter to match my heads?

89Nighthawk

The Wheeler Vortec heads are 195cc heads.

http://www.wheelerpowerproducts.com/...vortec_hds.htm

That's what I have on my engine.

Guest

If you port the heads you might make that much. Im running more compression and a zz4 cam on a Honed Ported Sr set up with the 58mm 30lb svt. 1 3/4 dual cats with a mandrel cat back, ported polished Vortec's, ram air, and made 389rwhp 442rwtq on dfi dynojet.

rik89gta

wow! Those are some big numbers! Does anybody know of a good head porter?

lilbowilson

iTrader: (2)

Why not just sell your heads and buy a set of Trick flow or brodix? Not only do they flow better than vortecs you will save a lot of weight too. Trick flow has already been proven to make 500hp on a 383 HSR with the right cam. I dynoed right at 330 rwhp on a HSR 327 with a old school hyd tappet cam with Trick flows. So imagine what a 383 would produce with the same setup.

rik89gta

Well I already have the Vortec Heads. I thought that they were pretty good heads. Plus they were cheap. Can't I perform just a little port work and get them them where they need to be?

lilbowilson

iTrader: (2)

I read in some magazines were all they did was do a little bowl work on some vortecs and made some real good power. I called Tri-State cylinder head before about bowl work and they charge about $300 to do it. Or you can try to find some place local and have it done.

Orr89RocZ

iTrader: (20)

most i've seen LT4 hotcam make is around 360whp and that was on a LT1 with ported stock heads which outflow vortecs.

i'd think u want something more modern for a camshaft as the LT4 is old and has lazy ramps. vortecs will make the power especially with a mild port cleanup job..but it will want abit more compression and slightly better cam. thats my guess from what i've been seeing from ppl on this board

TransAM Joe

iTrader: (6)

I making 390hp at the crank with stock vortecs, lt4 hot cam and an hsr, but the engine is blueprinted to race specs. It's all about how you assemble the parts with the correct tolerences.

rik89gta

Orr,
What do You think an optimal cam would be? My compression is gonna be roughly 9.7:1 and I have .550 limit spring's. I want something that run's a lil choppy but it also needs to be easily tuneable. I already have a 10 inch streetfighter stall on the way. It's rated at 3,000- 3,500 rpm's. I'm not looking for a 7k rever. I just want it to pull hard to roughly 6k with my semi stock Vortec's. The reason I ask You for advice is because You gave me suggestions on how to get my car running good before....... So I followed Your suggestions and my car went from a 15.4 at 89 to a 14.1 at 99 without any additional speed parts. Thanks again!

SheldonZ28

iTrader: (1)

The engine may make a bit more then 375 at the crank.

If you dont want to do much to the heads, just do some gasket matching on the intake and heads then have the valves back cut.

the stock valves have a little groove before the edge, which significantly decreases flow, with this back cut, its proven you can gain around 15cfm.

a bit better cam would be the comp 305 cam, its a bit closer to the max cam a tpi setup can take, and seems it will get you further in power.

specs are : 220/230 @ 0.50, .510/.510

jpk91rs

I call BS on the vortec heads not flowing well.
My old hot Stock dirt car ran an ultra light 355 with a nasty solid cam, vortec heads angle milled with 2.02 intake and 1.60 exhaust valves. That car spun over 6800 every Saturday night for at least 35 laps. I also have a 355 motor in my '72 PU with stock vortec heads, .100 pop up pistons, 230 duration @ .050 lift and .480 lift hydraulic flat tappet cam, stock valves, Performer RPM intake, and Holley Street Avenger carb 625 CFM. That sucker will turn 6500 and run like a naked monkey. Vortec heads are a very good budget performance head.

rik89gta

Now that's I like to hear!

SheldonZ28

iTrader: (1)

if your reffering to what i said,

im certainly not saying that the heads dont flow well, just saying that with a back cut valve you can increase the flow, and make them that much better.