4RCEPWRD

iTrader: (5)

hey fellas ive got a 350 HO crate engine and im lookin for a good
combo: cam, carb, manifold etc... to get me over the 400 HP mark
ive heard about the lt4 hot cam it sounds good but is there any
other combos anyone runs to produce that much hp? also any mods that my machine shop can do to my vortec heads to squeeze extra hp out of them? any input is appreciated thanks 3rd GEN. bros.

vincode8

iTrader: (8)

What kinda specs are you running now? Cam specs? Compression ratio? Type of intake(factory hi rise 4bbl) ? you say the Heads are Vortec? Any porting done on those?....Any ignition Mods or all stock? Type of exhaust? There are several ways to skin a cat.

89IrocZ350TPI

4RCEPWRD

iTrader: (5)

Cam-Intake lift- .435",Exhaust Lift- .460".
Intake Duration @ .050"-212,Exhaust duration @ .050" 222,
Lobe Centerline 112.5
Vortec Cast iron- 64cc Chambers,170cc intake runner, 1.94" Intake valve, 1.50" Exhaust Valve
9.1 to 1 compression ratio.
not sure about the manifold or carb think its a 600cfm edlebrock
hedman shorties cat back 40 series flowmaster, very soon to
be a true dual system with no cats
no porting that i know of and on the ignition its just stock.
kind of a newbie so hope this is enough for someone to go on
thanks

Anti-Venom

From Super Chevy Mag.
Scoggin Dickey Vortech heads.
Edelbrock performer rpm air gap intake.
Comp XE262H cam, 218/224 @.050, .462/.469 lift
Demon 750 vacuum secondary carb.
9.4:1 compression 350c.i. motor

max hp, 452 max torque, 422
Avg hp, 429 avg torque, 331

Tibo

iTrader: (15)

I think sombody proved that it wouldn't make that much by finally dynoing one themselves.

DNSTA

You Think!?!?!?!?!

xpndbl3

iTrader: (5)

XE274 cam, 3000 stall, 3.73 gears, heads modified for the lift, proper valve springs, performer RPM intake, 750 DP holley will make that goal everytime. add 1.6 roller rockers as well if the funds permit.

Air_Adam

vincode8

iTrader: (8)

Yeah for sure you need a bigger Cam and bigger Carb. Aftermarket intake would help, like the RPM or Air Gap. Also don't overlook ignition mods, like aftermarket distributor, Hot coil, and ignition box....You would be amazed at the gains from just that alone.

DNSTA

I don't think so. I have much better heads, a slightly bigger cam, that intake, that carb, and those rockers and do not make those numbers. This was professionaly done so don't get into that. Compression ratio and exhaust setup are huge factors in making that kind of power. A 9.1:1 compression ratio and a stock type exhaust will not net you those gains.

xpndbl3

iTrader: (5)

when my friends are running low 12s high 11s with that same combo i would expect it to make 400-425 horsepower all day long.

DNSTA

O.K. Before I go any further I guess I should ask a few questions and give a little info to back up my claim.

1. By better heads I mean Canfields that were bench flowed and outflow AFR 195 CNC'ed heads.

2. My compression ratio is 12:1 and I run a mix of 110 and 94 octane fuel.

3. I am still running a mostly stock exhaust. Short headers with y-pipe to a single 2-1/4.

With that being said, I did not achieve number like those on any of my 40, yes 40 dyno pulls. I'm sure the exhaust accounted for a good amount of that loss but I did say that you would need a good system to see those numbers which I don't have.

Also, let me know if this is a factor. I had all my work and testing done on a Mustang Dyno as opposed to a DynoJet. I have heard that there could be as much as 20% registered power loss from a test on a Mustang as opposed to a DynoJet. If that is true, or even half true, I would be making those numbers, flywheel of course.

So...What do you think?

Orr89RocZ

iTrader: (20)

i dont think he means 400rwhp... i think he wants 400 crank hp.

and yes mustangs do read low. and if you had a high stall converter your not gonna get the numbers ur lookin for. 87 TA got like 379 rwhp and i seen his car go 10.09 at 132mph. the converter makes the numbers weird. if your making atleast 350rwhp on that combo.. something is seriously wrong. and i know that exhaust is way too small.. get a single 3.5 inch setup for sure

xpndbl3

iTrader: (5)

DNSTA,
why build such a great motor and then snuff it out with a 2.25 inch exhaust. Factory 305 TPIs had a 2.75 and would gain a few tenths in a quality 3" single. For your motor I would run hooker long tubes and a h-pipe with 2.5 or 3" dual exhaust. I'm running a dual 2.5 inch now and will see if uncorking my motor this year and running open headers improves my times or not. IHI is running 10.90s through dual 3" with flowmaster 40 series I believe and his combo hasn't changed with the exhaust removed. I could see you having HUGE gains by redo-ing your exhaust. 40 pulls on a dyno is a lot of tuning money since it's 3 pulls for $100-150 around here.

DNSTA

xpndbl3 and Orr89RocZ you are both right. The car was origianly a 305 TBI and the exhaust is the stocker from that. I do plan on getting somthing new. I think I'm set on 2210's and a Mufflex Y and 4' Cat back. Anyway, it's good to hear that the Mustang reads low. I was very dissapointed with my numbers. I have a T-5 so no funny stuff from the drivetrain. As for the Dyno pulls I know that 40 sounds like BS but it's not. I brough my car to a local Dyno here by Brooklyn MI called DynoServe to have some minor tuning done and it turned into a nightmare. The guys kind of took my under their wings and really did a great job on my car. The exsessive pulls were done to demonstrate concepts and help me learn exactaly how everything comes together. Really good experiance. 3 pulls here are only $60

Sonix

iTrader: (1)

what rear wheel HP did you achieve as your best?

DNSTA

I'm at school now. I'll pull the sheets tonight and get some exact numbers.

DNSTA

Well it was worse than I remembered. 302.7 HP and 314.3 TQ. This is at the wheels on a Mustang Dyno with about 300 miles on the rebuild.

xpndbl3

iTrader: (5)

that is horrible. now sawzall off your exhaust and try it out again. I bet you'll see 50 more at least.

DNSTA

You're right, it is horrible, but if you say that the other combo is good for over 400 hp and gain of 50 hp after cutting of my exhaust would still not put me there, either there is somthing very wrong with MY comb or the other combo is not capable of producing those numbers which proves my previous point.

xpndbl3

iTrader: (5)

a 400HP motor will not put down 400 HP to the rear tires, so you putting down 350 after the exhaust snafu would be much better. Too put it into perspective, my buddy owns a shop which his shop car runs 10.80s all day long, and he put down 357 HP to the rear tires on a mustang dyno. His motor is a 406 with over 620 something lift and 265 duration. No where near streetable and has a 4000 stall, so I don't really use dyno's for anything other than a tuning aid to see where the numbers go, up or down, that's it I don't take them as gospel.

4RCEPWRD

iTrader: (5)

so Xpndbl3 that combo you listed earlier is tried and true? all youre saying is just put a good exhaust on so he can breathe?
also what kind of loss as in % can you expect between the crank hp and whats actually put to the pavement?

Sonix

iTrader: (1)

I think 15% is one # that's usually tossed around a lot. I usually guesstimate with 50HP, when in the "normal" range. A 350HP on the chassis dyno, may be a 400HP at the crank.

vortec heads, compxe274 is quite well liked, on this boards I can think of a handful of people with that exact combo.

4RCEPWRD

iTrader: (5)

thanks fellas I think I am going to try that one out. On another note are there any other things that the machine shop can do to the heads to squeeze out a little more HP?

92heritageRS

http://store.summitracing.com/defaul...h.asp&x=31&y=9

xpndbl3

iTrader: (5)

vortec heads are typically used straight out of the box. porting unless by a professional usually screws them up worse. I know some people clean up the bowls on the exhaust side but otherwise leave the heads alone. and yes there are tons of people on this board running low 12s high 11s on this combo.

Tibo

iTrader: (15)

The exhaust is really holding you back. I have hooker long tubes with 2.5" true dual exhaust. I had a glass pack muffler on each pipe, when I took them off, I saw a gain of +2 mpg. And that is from a good exhaust system. You could see a huge improvement as stated prior.

Sonix

iTrader: (1)

you can get the valves back cut, or ask about a competition valve job, 5 angle or whatever. Maybe go to a larger valve size? It's not that common, I don't think it helps on those heads though. Like xpndbl said, just use 'em straight from the box, maybe clean up a few casting flaws on the exhaust side, but be gentle.
aftermarket brand new vs junkyard? I'd take the aftermarket ones. At a junk yard, you have to get them from a new enough vehicle, that they aren't very common, and the wreckers know they're worth something, so they charge you a bunch. Then you have to take them to a machine shop to cut down guide bosses, open up spring pockets, hot tank, magnaflux, etc. New, you probably spend pocket change more then from the JY, and they're already done.
$260 each, assembled,
http://store.summitracing.com/defaul...=egnsearch.asp
$324 each
http://store.summitracing.com/defaul...h.asp&x=31&y=9

slapi01

i had that setup exactly before parting it out. heads,cam, demon 750, air gap rpm and had it dyno'ed on a mustang dyno. i think it was around 270hp/318whp

4RCEPWRD

iTrader: (5)

ive got a rebuilt 700r4 with a shift kit and a 2400 converter would that work or do i need to upgrade the converter? also how about exhaust, what ive got on there now is about to come off i want to run a true dual system should i go with 3" no cats, pretty much anything will go i live in Arkansas no emissions regulations so any ideas?

DNSTA

Correct. To clarify a bit more though, you typicaly see a 15% difference when using manual transmission as apposed to a 20% difference/loss with an automatic. But as previously disscussed, for bragging rights and an ego boost get the work done a DynoJet

4RCEPWRD

iTrader: (5)

okay ive got my funds up for all of the above, if it wouldnt be too much trouble could somebody give me part numbers for all: cam, intake for vortech heads,carb and I need a good suggestion on what springs and 1.6 roller rockers would be most beneficial.
oh yeah one more thing ive got a 700r with shift kit and a 2400
stall is it completely necessary to upgrade to a 3000 stall, if i didnt would i be losing out?thanks

F-BIRD'88

This isky cam will make 410hp in your motor with just a valve spring change. needs a 750cfm carb thou.
this is dyno verified.

Isky #201278. Use the stock rockers you have now. use comp #981 springs or Isky #205D springs but remove the inner damper and bolt them on. The cam is $99 at summit Use new hyd lifters. With only .450" lift this is a bolt in with no machining nessessary.

4RCEPWRD

iTrader: (5)

if i did want to go with the 1.6 rockers would that be beneficial to me? and machinings not going to be a problem i was going to take the heads off anyways to get a competition valve job on them.

stroker_SS

What did you use in place of those glass packs? I was going to do the exact same thing, but you may have convinced me otherwise.

Maverick_IX

This motor is capable of 377+FWHP without any internal work, Car Craft ran 377 with a 750cfm carb, heddman headers, and an rpm intake manifold, also I have run that same crate with a large bore TBI and put out over 350fwhp with a pretty modest exhaust/headers. Just thought you'd like to know, before you start going overboard with dfifferent heads, huge cams, etc. That same Car Craft article stated that using a variety of differnet cams showed minimal gains. Using the GM Performance Parts hydraulic roller Hot cam and package bumped this motor to 400.

Side Note: 3000 stall, 3.73 gears have nothing to do with HP, just going fast.

wgripp

iTrader: (1)

http://store.summitracing.com/defau...ch.asp&x=31&y=9

What kind of horsepower gains can I see using that kit on my stock TPI engine?

4RCEPWRD

iTrader: (5)

XE274 cam, 3000 stall, 3.73 gears, heads modified for the lift, proper valve springs, performer RPM intake, 750 DP holley will make that goal everytime. add 1.6 roller rockers as well if the funds permit.

So are you saying this combo is not going to get me to the 400 hp mark(at the crank)? I was going to keep the heads just swap out all thats listed above.

xpndbl3

iTrader: (5)

maverick is saying a different combo made 377 HP. you wanted 400 HP so i put out a combo for you. The 3000 stall and 3.73 gears are so the motor stays in it's powerband and is easier to drive and more fun to drive for that matter.

Maverick_IX

What I was sort of saying was 400fwhp is VERY doable with this motor but put your money into a good intake and good headers/exhaust before changing the cam or messing with the heads. Stock Vortecs are capable of 400HP. Plus, you might want to check but some of the GM 5.7L H.O. crates already have the 1.6 RR's. Which probably accounts for the underrating, some have them some don't but the cost the same and were listed with the same Part Numbers?!?

4RCEPWRD

iTrader: (5)

interesting..how do I go about checking my rocker arms to see if they are 1.6?

88IROC350TPI

another vote for the XE274/Vortec head combo... so long as you have around 10:1 compression ratio. Cheap to build, completely streetable, and it'll give you atleast 400HP