Strongly considering sliding this engine into my 91 vert. Wanted to know what the general consensus is on installation, and performance.

Any problems etc?

I know I've posted a few questions in regard to swapping. Thanks for your patience.

 

This has sat around with no response for quite awhile.

It won't just "slide" in there. Vortec heads bring on a whole host of issues that need to be addressed. 1st question you have to answer is, "What induction do you plan to use?"

Personally, I'm just not all that impressed with that engine. You could build a 350 that doesn't have any of the Vortec issues, make just as much power, and have real performance features such as screw-in rocker studs, roller cam, etc., for less money (no warranty, perhaps, but how much is that worth?). But, that's just my little anti-Vortec bias showing.

At least you've picked a good hot rod builder...

 

thanks five7: was actually glad that you replied to this topic. I've been back and forth on this engine deal for a while. Its probably going to happen in 2-3 months. So I'm trying to scramble and figure out the best possible engine config for my money. Obviously I have the $3400 for the sdpc engine, so thats what I am working with. But if I can do it better for cheaper, you know I'm interested.

I have no experience in building engines (although I replaced the entire suspension on my car myself) and one of the reasons I went with sdpc is because its already put together.

I had considered just buying a rebuilt 350 short block, but I really had no idea about where to go from there. I don't know which heads are recommended and which ones require the use of a special base plate.

I'd like to keep the TPI intake and all the emissions junk. I know you prob get tired of amateurs like me, but if you had any suggestions or shopping lists, it would be great.

And, my hp goal is around 350.

 

Hate to follow my reply with another but; What I am having trouble conceptualizing is that the stock 350 from a 91 F-body ran around 220-240 hp. The crate engines (non-vortech) I have seen are running 80-100 more ponies.

What changes were made to create such an increase in hp??

In other words, what would I have to do with a stock 350 with TPI intake to make it run 100+ hp than it already is?

 

That should be farily obvious....

The thing that costs the HP, is the TPI. Lose the TPI and you stand a chance. Keep the TPI, you're stuck with at least 100 less HP than the otherwise identical motor would make with a performance oriented induction system. Look at the ZZ4 compared to the Vette L98: almost exactly 100 HP difference in their "rating", the only real major difference being a carb intake vs. TPI.

Of course, that's not always possible; local emissions laws, for example, can make it extremely difficult, there being few acceptable substitutes. Even as far as aftermarket FI systems for Gen I SBCs go, about the only smog-legal one is the SuperRam.

That's a real unfortunate thing about these cars, that they all came with such low-performance inductions systems.

 

The good thing about your '91 is that it has the speed density TPI setup. It can handle higher power levels than the older MAF system. The downside is that SD is not as friendly to changes such as displacement increases. The good part about that is PROM tuning isn't that hard.

The typical TPI system benefits from porting of the plenum and base, adjustable fuel pressure regulator, runner changes, and PROM tuning. A good free-flowing exhaust is also a must. When you get to higher power levels, a larger throttle body and injectors is typically in order. A "stock" 350 with cam upgrade and head porting with the above will easily produce the 100 HP addition.

It's not really fair to compare crate motor power ratings with the stock ratings in our cars. That 330 horse 350 HO is gross flywheel power with open element air cleaner, no accessories, and long-tube headers; while the 230-245 listed in the tech data is net horsepower with the accessories running (water pump, alternator), with the like-installed air cleaner and exhaust. Put those same restrictions on the HO, it'll probably put out about 250 HP (maybe slightly more).

Certainly the TPI can be improved. I know a certain racer who started with an '89 Vette, put in a 406, then when nuts. It's got a Miniram, AFR heads for starters, and is a tweak-out full-time race car. But, it is still a SD TPI system, and he runs consistent 11.7's with it. Last year, at the season-ending points race (which combined Friday and Saturday series), he was running round-robin between two classes. He'd make a run, win, go back to the staging lanes, make a run in the other series, win, go back to the staging lanes, etc. He didn't ice down the plenum, hose down the radiator, nothing between rounds. Didn't even change his dial-in. I was still in one of the series, he asked me between rounds, "Which series are we running right now?" He couldn't keep track, he just knew he had won and could keep racing. He ended up winning one series and was runner-up in the other.

Don't tell me TPI can't be made to work.

 

A MiniRam is not Tuned Port Injection. There's no way to compare the 2. They work in entirely different ways, as far as what's deficient with the TPI design: TPI used long runners that are acoustically "tuned" (the "T" in "TPI") to produce enhanced cylinder fill (and therefore higher torque) at one specific RPM, at the expense of torque at all other RPMs (most especially above 1.5 times the "tuned" RPM). The MiniRam uses no such "tuning": it works like a traditional single-plane short-runner carn intake, it just happens to be shaped in such a way as to accomodate the horizontal-flow throttle body, and of course it has injector bungs.

It's definitely true that TPI can be somewhat uncorked from how the factory delivered it. But the fundamental characteristics of its design will always be there, no matter what, as long as it's on there; just as surely as you can only get just so much power out of a 2-barrel carb, sooner or later, you're going to have to step up to a 4-barrel to overcome those limits.

And it's not really fair to compare a re-programmed, head-ported, all kinds of otherwise modified TPI that almost makes it to 300 HP, to a production-line 4-barrel with the same heads, out of the box. Take those same mods that get the TPI almost up somewhere at least near the carb motor, do those same things to the carbed version, it will once again leave the TPI-equipped motor in the dust.

 

I suppose we can agree that "life isn't fair".

Now we just need to get used to it.

 

i did the swap with the 350 ho deluxe. the engine is flawless. no problems. lots of power. if you strap that motor in and upgrade your tranny change the gears to 373's(basically everything i did and you should run a high 12.(at least i did ) might want to upgrade your tires though. pm me sometime and i will tell you everything you need to know. here's some pics.

 

Chef, I can understand why you're happy (any 130 mph trips to Target lately?). But, he's sticking with TPI, which poses some problems that need to be worked around, and increases the cost of the "crate" concept.

 

hey be nice. no 130 trips any time lately. more like 30-45(speed limit ) anyways i just wanted to throw in my 2 cents. not tryin to mess with ya'lls opinions. i know you are all very knowledgeable. i have never owned a tpi although i heard they can be made to produce some incredible numbers. better throttle response, fuel economy, quite, i just happen to like carb. my .02

 

he might want to check into the fastburn engine

 

I had no idea what a restriction the TPI intake put on overall hp ratings. A freind of mine is working on adapting the LS1 (or LT1?) intake onto his firebird.

Thanks five7 and others for all the valuable info. I'm still scheming here and have not quite made my mind up about what to do.

I'll be able to give a more educated response after I do some more research. Be patient. Thanks again.

 

Maybe I'm askign alot, but what I'd really like is the power of an LS1 with the same fuel effiency. But getting there seems to be the problem.

 

I have the fore mentioned 350 HO w/TPI and it ROCKS!!!!! The statement of it having "only 250" horses is bogus. I dyno'ed my L98 with all the same mods and my best was around 210-215 if I remember correctly. This Crate would walk all over my ole' L98....I do not what it is but in the higher RPMs, I feel this engine pulls a WHOLE LOT MORE...I am talking 70-105 mph is basically a blink compared to the L98. I have yet to Dyno or run at the track...but the time is getting near. I have only a handful of races (people do not race around here ), And I have owned them all. If you do go with the 350 HO TPI....Make sure you get a chip burned. Fastchips is IMO the best out there.

If you have any other questions then ask me....Be sure to check out my page...Link is below!!

 

does yours have the vortech heads?

I tried the other day to find ed wrights online, but I think I have the wrong addie: what is it?

Right on for giving those competitors on the street a run for their money. I don't think they want to see the end result of ALL 8 cylinders. Too bad for them.

Wondering if porting the plenum and siamesing the runners would make a huge diff....

 

SO would it be a wise idea to scrap the tpi intake and just go with the stealth ram?

Well....that would not work with the vortech heads. What I'm thinking is buying a rebuilt 91 5.7L short block with a better cam, trick flow heads, and the stealth ram setup.

How does that sound?

 

Also curious...every GM 350 HO I see advertised say that they should only be used on 1973 and earlier pre-emissions vehicles. Is that only if you use a carb?? I mean if you retain the TPI intake with all the emissions stuff, what problem could there be??

 

Yes it has the vortech heads (paid extra 400 smacks for the Vortech TPI intake!!) and they are great!! Just had an encounter today with a warmed over mid 90's GT (see kill stories). The two main things you need to retain the TPI is the Vortech intake and what is called an EGR kit. The kit essentially taps into your header and is ran to the EGR. Must have gasket kit also!!!! try WWW.fastchip.com

hope this helps

Later

 

check this out:
http://www.allchevyengines.com/350-350.htm


I'm going to find out if they'll swap an edelbrock performer TPI intake manifold for the one its currently offered with.

That and a 52 or 58 mm BBK throttle body and I should be good to go.

I like the Vortech heads, but I'm worried about restrictions down the line if I want to change intakes.

This is probably the most confused I've ever been. Tough b/c its alot of time, money, and work to sink in and I don't want to make any mistakes.

Most everyone dogs the TPI (engineering milestone) for some good reasons. I can't go carb due to emissions and I cant justify spending $1000+ on an aftermarket EFI setup because the the stock TPI peaks only at 4500 RPM. At that number, I'm just about to redline.

SO hopefully with that head/cam combo and the modified intake, I will end up more than just satisfied. We'll see.

Any probs so far with your new engine? Who've you whipped up on lately?

 

My TPI vortec headed L98 pulls past 5000 rpm.

And you don't lose 100 HP from TPI to Carb on a mild 350 setup...do you guys realize what 100 hp is?

According to my calculations I am putting nearly 300 hp and I have more stuff to do.

While it is true you can make more peak HP with a different induction system, the torque levels and hp of a TPI with vortec heads makes for a very quick street car.

As it stands right now I eat LT1s for lunch and make a race out of it with LS1s. I still need to change my YPipe which is a major restriction and do some work to the stock plenum and runners along with 1.6rrs but when all is said and done I guarantee I will be over 104 mph in the 1/4 and low 13s. All this with a stock L98 shortblock and cam.

I personally think the TPI with vortec heads is a excellent street setup. Don't need to be revving 6000+ to make the car move!

 

Im so glad you said this, you sold me on the vortec heads, diesel like torque rules, thats why I got a tpi car.

 

I am planning on using the GM 350 crate engine. With Vortec heads and the Stealth or Mini-ram if possible. TPIS does make a Vortec Mini-Ram intake. I don't know if there is one for the stealth ram.

TPI Can make alot of power. It just takes more money and I think it's a bit harder.

As for swapping the engine out and staying legal your really can't. It's technically not legal to replace the engine in most states without it being an OEM part. So performance engines of any kind are out of the question. But all 305's and 350's look close enough that you can pass visual inspections in many cases. IF your vehicle is in good tune you can pass the sniffer. But no it is not legal.

I hope this helps. I have done my research and I am going to be doing the swap in the next couple months. I already started buying items needed to get the most out of my purchases. I will be getting the engine shipped in close to the middle of the month. (I get paid again).

You can get an engine built for less maybe. I just am not comfortable doing that at this time. My first engine swap is going to be a crate I think.

 

i already bought my 350HO, i need to take some pics, i've already got a Vortec RPM-Air gap 750cfm edelbrock carb, summit HEI distributer and headers, but i still need all the same crap, air cleaner, water pump, harmonic balencer, new flywheel(errrr... they had to change the bolt pattern in '86), motor mounts and a fuel pump.

tomarrows paycheck should cover the rest

im sure theres lots more crap i'll find i'll need while installing it though.

thinking about throwing a 75hp shot of N20 on top of that, but

that costs more $$ in more ways than one

 

Is there a Vortec intake manifold for the superram? Or does it use the stock TPI one?

I can always find plenty of stealth ram info and mini-ram information but I know nothing about the Superram. Who makes it, how it compares, how much it costs, what it even looks like.

 

I'm looking for a TPI engine myself. I called several engine shops I found online and the the advertised horsepower rating is used with a carb. They said if I used a stock TPI, calculate loosing 80 to 100 hp, well I don't have a stock TPI, so I figure I'll lose around 30 hp on any engine combo.