hey fellas... im looking to get more torque and lil HP out of my 350 tpi... I have to already replace the head gaskets so im kinda set on iron vortec heads to replace the heads all together.. have those ported, also gonna port the plenum, and runners and add a bigger throttle body... from there what else should be done to achieve my goals..

 

It is not likely you will get a gain by swapping throttle-bodies, but you might buy using a ported intake base, or an aftermarket base.
Exhaust headers often add a good bit of torque.

edit: by the way your stock TPI base will not fit on vortec heads, so you will need to change that anyway.

 

If you are swapping to vortecs, you will need to swap to a vortec base.

This combo should give you a good gain in hp and torque.

TB is a waste.

A cam and exhuast will be your next step.

 

i have flow master exhaust already...3in pipe. yes i didnt mention it but im changing the base as well, as i have to lol.. the TB is a waste even if the plenum and runners are gonna be ported?

 

Most say the stock TB is good for at least 350 hp at the flywheel.

With a stock cam, you're okay with the stock TB for sure.

Add some headers.


Be careful porting the vortec base, they are pretty thin.

 

i may not need to if i go with edelbrock hi flow vortec base... should my cam be mild or hot? what part should the cam match up with

 

The edelbrock / scroggin dickey base are the same. Both are thin and of a poor design, IMO. They need work, but you have to be careful. From what I have seen here, most end up adding epoxy in places where the castings are so thin you cut right through it.

Cam is based on a few things, most importantly, what you plan to do with the car.

Is this a daily driver, a weekend cruiser, a street strip car, a road race car, etc......

 

recreation car...not a everyday driver per say.. a few days a week when it gets warm.. i have 3 other cars so its my project basically. What would be a good base to get? i don't wanna get anything i will have to replace or fix up etc..

 

The only option for a base is the edelbrock/scroggin dickey base, if you want Vortec heads.

With stock tpye heads, you are limited to edelbrock, or if you can find one, and old accel.

Stock base is fine with a little porting for most.

The Vortec base is ok with some careful porting, and the vortec heads are nice.


Camwise, I would look at the Comp 8-501-08 or 502-08.

Both will require some ECM tuning.

take time and read some of the other builds here, many have taken this road before.

 

Another option to consider is a Holley Stealth Ram.

 

that stealth ram peaks in the higher rpm range correct?.. i really want that head snapping torque and a little more HP.. stupid loads of HP isnt necessary for I'm not racing. I want great torque decent HP..

 

Yes, the stealth ram will move your powerband up some.


How many miles are on the shortblock? Why do you have to replace the head gaskets?

I would consider a basic re ring, swap in a comp 8-500-8 or 501-8, vortec heads, and the vortec base.

A little port work, headers, and you should be very happy.

 

because i blew the head gasket a little over a year ago.. even though it was minor blow i still wanna replace the heads since i would get those checked for cracks and such anyway..figured i'd spend the money on a upgrade

 

i have the scoggin dickey base with vortec heads and the lt4 hot cam 1.5 RR its decent. 0-60 in 5.5-6 seconds with light launch due to traction problems

 

is that with everything else stock? plenum, TB, etc?

 

...then you're going to want to go with a very mild camshaft with no more than 212* intake duration @ 0.050", and as much lift as your heads will allow.

 

the duration is what causes the loping sound correct? longer the loping sound more power it produces in higher rpm ranges? More steady idle the power is in the lower rpm ranges?....

 

Duration, and LSA play big rolls in the idle 'quality', but in a general sense, yes, bigger duration, rougher idle, more power in higher rpm.

Remember though, even a ported aftermarket TPI is RPM limited.

 

yea i think i got a pretty concise understanding of the TPI limited rpm range but i figure im not racing wont really need crazy amount of power above 5k rpm range.. i dont need highway tickets lol state troopers pull you over damn near a guaranteed ticket.. I figure i will have to do some chip tuning as well right? but in a month maybe sooner i will be pulling my engine and breaking it down.. get it magnafluxed and all that jazz... have it bored .30 over flat top pistons.. vortec heads and base..TPI runners and plenum ported i should be ok..i think.

 

Yeap sounds good. Depending on the cam, you may need tuning.

 

so the cam is what controls the timing or directly effects the timing? with this particular set up I should go with a mild cam as you suggested right? would that require a chip tuning?

 

Well there is cam timing and ignition timing.

A comp 08-500-8 would be a good mild cam, that may play fine withthe stock ecm.

Tuning is always recommended when modding, and there are a few guys here that can help.

 

Late to the party, but goto gmhightechperformance.com and find the tech article on their TPI Vortec 350, called Something Old Something New. 430 TQ @ 2500, 487 TQ @ 4000, 416 HP @ 5000, 340 TQ @ 6000 = 386 HP. And it made the stock 245 HP @ 2800. Cam was an off-the-shelf Comp HR 210 / 220 114 500 / 510, and it did use a 58 mm TB. Total timing was 26 degrees, it idled smooth at 700 RPM, and BSFC at TQ peak was just 0.40 I had an acquaintance copy this, we saw 414 HP and 482 TQ. If any of you know of a torquier 350, I want details.

 

this sounds great...im definitely gonna look into this.. doesnt sound overly expensive.. was your acquaintance pleased with the results?

 

yes all unported, and i still need to tune it better

heres a video of it

 

If youre hunting for good power through 5k no need for a lumpy cam
Using those heads Id personally look for something with a good solid 10 deg split on it the exh ports are a little weak on those.

If you are porting them get someone who really knows heads so they dont booger them. Not as easy to get # out of them as a typical head.

 

Sounds like you need to adjust your valves.

 

Don't post that. Because the intakes are already good, it's easy to see good results with little work, but it's difficult to gain good improvements. Far more precise than your wording. The exhaust ports start out poor, but have as much potential and a better short turn than any other production iron SBC head.

 

when i took the video it had come big exhaust leaks, and also the injectors are attributing to the loud ticking but my boss from my shop said its coming from the dizzy i have to look into it

 

There isn't any one part that is nearly as important(just a cam or just heads) as a match parts built engine.Cam compatibility with compression ratio's along with quench set at the target of .040 are key elements in a target tailor torque curve build as what your asking for.
A essential part of lower torque curves goes back to the law physics each hasn't changed.Smaller c.i. engines produces high power curves.Where as the really outdated approach of slamming a cam in doesn't work. If your going to go through your engine in any case,the added expense of about for a quality 383 stroker kit @ about $1,500 to $2,000 is well worth it for the long term results.

Magazine articles by design and main goal is to sell parts.Never lose sight of that fact.About 1/4 of what is published have somewhat valuable info and even at that doesn't tell the complete story.

I can't capsulize 50 yrs of building engines in this short post,nor given it is our busiest time of the yr,adopt a thread with advise,but I do have time to surf and will "try" to help out as you go through your build.

Suffice to say there are big picture plans you need to make and key machining needed to be done.

 

Oh surely lol.. this is gonna be in the dream cruise this year.. but even before that time comes i wanna enjoy it..I will pull my engine a trans within the next month and start breaking it down.. but it makes sense to have compatible parts than to just over do it with one particular part.. after i get the machining done and parts etc.. will there be a need to tune the computer a bit or will that be fine? what about the transmission? corvette servo perhaps, and stall converter?

 

which head would you being referring to? vortec? which head would you suggest?

 

It might be just my impression,but it seems to me your glazing over exactly what parts and exactly what machine work your speaking of.

Could you post your build plan including that??.

 

GM vortecs and nothing wrong with them. Attila did word it better....basically saying run em as is or get someone who has a history of working with those heads if youre trying to pick them up in power. The avg amateur will wreck them; pretty good design out of the gate.

 

i have the general idea of what i want.. this is just a street car. i wont be racing on a strip but i do want to increase torque more so than going for crazy HP... What im getting done is my block magnafluxed and all that jazz bored .30 over and flat top pistons.. that is the base of what im doing.. beyond that i want to match up the proper parts for my low end power.. i dont need power over 5500 rpm... from what im getting i guess i'll be going with a mild cam..iron vortec heads and base(ported).. then the plenum and large runners...

 

oh definitely if i get them done i will surely get the work done by professionals.. i dont mess around with amateurs with certain things..

 

Thats what I ahve been trying to say.

Not everyone needs $1200 heads.

You will be very happy with out of the box vortecs, base and mild cam. And you might have money left over to put gas in your tank!

 

well the money isnt a issue but if i can get results without spending unnecessary money then im all for that...

 

if I'm getting my engine bored over dont i need to do the same with the heads or not necessary?

 

Um, no. The heads do not get 'bored'

 

I know that...come on now do not try to play me for stupid... when i said dont i need to get the heads done i assumed you knew i meant machine work to match if that was necessary.. so let me be specific.. If i get my ENGINE bored over do i need to get my HEADS ported/machined to match or does that not matter

 

Make sure the block is decked aswell. As Gary said above, you really want to go for that .040 quench. That is the deck clearance and gasket compressed thickness combined. You can find gaskets of nearly all thickness above .010, but thinner than .025 and they start to get pricey. This means your deck clearance needs to be between .000 and .015 for common decent gaskets without spending a lot on them. Most factory blocks are about .060 deck clearance. Also, have them mic the crank. If its out of spec, get a 383 stroker crank. The price of reworking an old stock crank is just not worth it. You may aswell get extra cubes out of it if you're getting a new crank.

 

Again, no.

 

again?....LMao.. thanks for the condescending response..dont worry i dont take any of this personally.. well guess i'll save some money on that front since it isn't necessary.. if there is porting/machine work that may need to be done what would that be?

 

Vortecs are good out of the box. No porting needed imo, for this application.

 

what about the plenum and intake runners? leave them be or get larger runners? that airflow is pretty restricted correct?

 

Do some searches, the vortec base could definatly use some porting, but it is thin so you have to be real careful.

Aftermarket runners will certianly help, if you can get a good deal.

The upper can use minor proting behind the tb.


Problem is, by the time you buy a vortec base, and aftermarket runners, you could have swapped to a stealthram, which would raise your power band.

I would not buy new aftermarket runners, but if you can find a deal on some used ones, grab them, I have seen a few on here lately.

 

doesnt that stealth ram rob some of the low end torque?

 

It shifts the powerband up, generally. Yes your torque bellow 2500 will be lower, but your overall torque and hp will be greater.

Not a bad trade off considering our cars can be 'traction limited' as it is, IMO.

 

thats true... its extremely easy to spin these tires.. the stealth ram i have seen are all 2-3k.. am i looking at the wrong ones?