likenoother

Okay here is the question I have, I found a new 350 vortec truck engine with under 18 thousand miles on it. I would like to swap all my new parts for my other 305 which is a 1991 Z28 tpi engine. In place of that engine in to my car. I have all new parts like Edelbrock TES Chrome headers, Stef's pans, Edelbrock Elite Valve covers, Accel spark plug wires with PRO Sleeves, PRO Sleeve Boot Guards, Engine and Transmission mounts, Remote cooler and filters for Engine and Transmission, Bosh Platinum+4 Spark Plugs, Bosh O2 Sensor, High Flow Corvette Catalytic Converter, K & N Filters, Mobil One Oil, T700R4 Transmission being PRO Built with Corvette Valve Body and Internal Parts and Custom Toque Converter, 9 Bolt Rear End Rebuilt Three Years ago and all other parts related to change or replace during Engine change and Transmission Rebuild. I have also read and been told that I have to swap the intake to a Scoggin-Dickey TPI Vortec Intake Manifold. I also have other plans for my car too. But that is later, So I'm looking for feed back.:hail: :hail: :hail:

PhilM

the intake is really the only special piece, everything will swap right over. Vortec heads use an entirely different bolt setup. I think Scoggin is the only place to get that Vortec style TPI intake right now. Should be a good swap, those motors run great...

five7kid

iTrader: (14)

It should make at least as much power as the 305...

SDPC designed that manifold to allow people to put TPI on the 330 HP 350HO crate engine. What they discovered is standard TPI barely made 300 HP even with aftermarket (Edelbrock) runners and long tube headers. So, they tried it with a ZZ4 cam, which required head modiications, then it made 335, as much as the carb'd HO with the standard crate cam.

All I'm saying is don't expect really great things from the truck engine without some tweaking.

DSLDUDE2001

Is the TPI system just that restrictive, or is it simply a tuning issue? Me and my dad are planning out a new engine for my RS, and a votec TPI setup is what we are sort of leaning towards.

five7kid

iTrader: (14)

Personally, if I didn't have a Vortec engine and wanted to do a Vortec TPI, this is where I'd start http://www.sdpc2000.com/cart.asp?act...=1577&pid=9009 .

Still requires the rest of the TPI system, however, and doesn't include the upgrade runners, TB, and so forth.

The TPI system was adequate for a 305 emissions-friendly streeter. It needs significant help if you want to go beyond that. And, I was also addressing the "truck-ness" of the engine the originator has.

dyeager535

Don't forget, Vortecs have no provision for EGR, and that SDPC intake is *$400*.

Also, all are 1.94/1.5 valves, (probably not a big issue for stock TPI) and the valve springs are pretty darn weak. Stock lift on the Vortec motors was .420 or so. I put a .450 lift roller cam in my motor, and cam company said I needed new springs. Additional expense on top of the $400 intake.

You might seriously consider finding another motor, buying a different pair of heads, and using the stock intake, or whatever.

Depending on where the motor is coming from, ALWAYS be leery of used engines. The seller could just as easily be selling you a piece of junk as a great runner, and it happens ALL the time.

I'm ALMOST done putting together a Vortec TPI motor, and I wished I would have gone with different heads. These things are too big a pain, and too expensive to modify, when aftermarket heads would perform as well or better (and be better to boot) for about the same price.

I bought the Vortecs when I intended to use a carb. I should have sold them once I decided on TPI.

poncho@home

I have to strongly disagree with the previous post. The vortec TPI is a great combo that makes plenty of torque and HP if setup "properly" and the cost is not any more expensive than other build ups.

Everyone complains about the cost of the SDPC TPI but in all honesty if you are going to install heads/cam and exhaust on a non vortec headed engine you still need to upgrade the TPI intake. Or if you swap to carb, still need to purchase an intake and carburator...a good carb today goes for 400-500$ alone...

An engine is a complete package...vortec heads with TPI can make plenty of power....as can other combos...but they all cost money in the end...for me it was a no brainer to retain stock appearances and have a better performing engine the Vortec/TPI was the route I took

The only thing the "truck" engine needs is a cam to be a good performer.

Kontrax

why not just swap the whole damn motor in and leave it the TBI? your talking about a vortec from a truck correct? those things made more power then the 305 tpi. and now they make these management systems for TBI and get gains of 100 hp. i think holly makes the management system? thats if we're talking about the newer vortec motor here, not sure about the older ones. granted i dislike TBI over the TPI, but the newer TBI vortec truck engines produced more power then the 305 TBIs

dyeager535

That's ok, you can disagree with me if you want.

Tell me how well the Vortec TPI base flows? SDPC cetainly can't or won't tell you, and to this point, I haven't seen anything that proves it flows ANY better than the stock one. Besides, what exactly is the point of changing to a better base without improving the runner setup?

You are right, an engine is a complete package. Pressed in studs, 1.94 valves, 1 "cheap" (at $400) intake manifold option, and weak "proprietary" springs don't make a HP motor, nor is it very cost effective IMO.

For a stock motor that doesn't need much lift, won't be run hard, and won't rev a lot, the Vortecs are probably fine. Still looking at $400 for an intake on a motor that probably won't use it if nothing in the heads are changed. Anything outside of that, I say go with something setup to be a better performer from the get-go.

Those truck motors make decent power, but they are TRUCK motors, and TRUCK heads, and they are designed for low end torque. They would have used them on everything if they weren't so application specific.

Ray87Z

With a equal cam, this TRUCK engine and TRUCK heads will outperform the same setup with Vette AL L98 heads and most every other budget head. End of story... For budget power bolt on and go you can't really beat em. If you want to step up the cam to more than the stock springs and retainer/guide boss clearance will support then you spend $200 to get the seats cut/clearancing done and some decent springs put in (or do it yourself for quite a bit less). That doesn't exactly break the bank or require a rocket scientist, you don't need screw in studs/guideplates or other expensive mods unless you're getting fairly wild on the lift. They'll support well over 400hp with just the springs/clearancing work done.

Now as to the SDPC TPI intake itself, that is up in the air. I'd like to see some solid flow and dyno testing myself. I'm sure you could port it decently enough without too much trouble to match most of the other TPI baseplates no matter what though...

I'm hoping Holley releases the StealthRam for Vortecs they hinted at awhile back, I'd like to convert back to fuel injection when they do...

poncho@home

I don't have flow numbers for the heads....but I did measure the diameter of the port on the runner side and it was 1.65" compared to 1.5" for stock. That alone is a huge increase.

As for the upgrades needed to these heads:

My heads cost me a total of 600$ CDN for upgraded springs good to .540 lift and screw in studs including the original purchase price of the heads. Find me a better flowing/performing head for the same money($400 US).

As for the 1.94 valves...bigger valves will simply hurt velocity on this head...you really must understand how heads work to understand that bigger isn't always better, and I am not giving lessons today.

There are plenty of vortec build ups into the 400+ hp range.

The question is not the heads or the base for that matter, its the runners and plenum that need upgrading...and those parts are readily available. Even with the most expensive AS&M runners it's still a budget buildup that should make plenty of good strong usable power.

And if Holley does indeed release a vortec version of the SR then your options are expanding greatly...either way, it's been proven that the vortec heads work well.

five7kid

iTrader: (14)

There's already a Miniram version out.

I just wanted to make sure it was understood that a standard TPI with SDPC base on a standard Vortec wasn't going to be a "killer" combo.

Standard TPI is the first problem. Standard truck Vortec cam is the 2nd. Upgrading the cam requires upgrading the heads, etc., etc., etc.

Like all "hop-ups", it's an exponential snowball effect.

dyeager535

Exactly. Vortec heads are good performers, but they aren't *that* good, as they come with many penalties.

As to $600 Canadian, well, here, that would be $450, and you can't get a bone stock set for that. $500/pr is about as cheap as I've seen them, and you pay $50-100 in shipping.

Yeah, you are right, I don't understand how heads work. Thats why good aftermarket heads flow more than the Vortecs, with smaller ports. (probably EGR crossovers and a "standard" intake bolt pattern/port to boot)

You talk about how good they are, yet you don't have flow numbers, probably haven't compared them to others, and paid less than what they cost here. (and yes, the Vortec head flow numbers are available all over the place, I don't need to cite them here)

There ARE plenty of Vortec buildups over 400HP. How many of those are TPI, and how many of those use BONE stock Vortecs? If they aren't bone stock when the engines are built, acquisition cost means nothing. (and yes, I've seen the buildups, all I remember, used better springs, and had to have the heads modified for them)

So without knowing what the base or heads flow, you think that upgrading the runners and plenum is the approach eh? What happened to it being a package?

This is all bench racing of course, I have yet to see a dyno tested buildup that uses TPI and multiple sets of heads. Plenty with carbs, but that is NOT what we are talking about here.

poncho@home

Just to hash up old arguments....I have a set of stock vortec heads aside for the upgraded springs, stock L98 cam, stock plenum and runners, stock bottom end. Basically all I changed was heads and full exhaust.

Car weighs 3750 with me in it. Full street trim. Ran 13.348@103mph today on BFG DRs.

There is still more left in her btw, I do plan on trying a ported plenum and runnners in the coming weeks.

103mph@3750lbs is 320 RWHP...+15% drivetrain loss = 368 HP....not too bad IMO

dyeager535

No, I'm not arguing that they aren't a great head. There have been plenty of tests that show the heads ALONE are worth 40HP over other designs. That in itself is hilarious when you see people still paying good $$ for camel humps in anything other than racing classes that don't allow Vortecs.

I just don't like the multitude of other things you need to retrofit them to anything other than a carbed, pretty much stock motor.

Still a huge improvement over old school designs, but if I had plans to go as fast as possible, they would be near the bottom of my list.