I'm looking for some ideas for my engine for my 86 trans am. I have some criteria.

1. Must use the factory TPI (as much as possible after seeing some responses)
2. Must run 87 octane. This car is a driver.
3. High torque.
4. Must idle nicely ECT ( street car/driver)
5. Low RPM powerband. This car will never reach 4500 RPM.
6. Naturally aspirated.
7. Good sound. Deep rumble. (Planning a nice set of headers and 3 inch true duel exhaust. All stainless steel.
8. Computer will be retuned.
9. No chopping of subframes or k members ECT.
10. Must bolt up to a 700R4.
11. Budget is flexible but not looking to blow the bank. (Best bang for the buck is how I roll.)

Otherwise, have fun and I look forward to hearing what input you have. Can be a built 305 350 383 400 ECT. Not picky as long as the above criteria are met.

 

Find a good running vortec. 305 or 350, you don't list a power number so either will achieve your goal. If it's used, inspect and reseal. Maybe install a fresh set of valve springs. Replace TPI base with a vortec base. Put a quality flowing exhaust, tune and drive.

Don't bother porting factory TPI runners, little to nothing to port. You don't even need to change the cam if you don't have any power goals past what you have listed. If you put a cam in it then head work would likely be needed to accommodate lift.

 

Yes. Used L31 Vortec.

GD

 

I would take what ever power I could muster but not at the sacrifice of the primary goals.

 

The L31 is 255 HP stock. And you want low end - it's a truck engine with a truck cam. So just get the lower TPI base and install a stock L31.

 

The stock tpi runners can’t really be ported. Not enough material. You can grind down the lip on the inside and slightly enlarge by running a steel ball through them. Better off getting as&m or other aftermarket runners used.

 

Agree with the L31 Vortec 350. You can get a brand new GM long block for $2K. Add the vortec base and you’re good to go.

 

new GM vortecs have been discontinued. I haven't seen any replacement crate from GM for it.

 

That might be but I did come across this:Subject: NEW - VORTEC 96-02 350 L31 CRATE ENGINE

https://www.gmperformancemotor.com/parts/12691673.html

 

Wow, the price doubled since last year. That’s for new GM anyway.

There are a bunch of remanufactured L31 motors out there for around $2K as well. That’s still a reasonable option as long as it’s a reputable reman company.

 

I can't say I shopped around at all. Just did a quick search. There are probably deals to be had out there.
And for the record, while it says ready to ship doesn't mean it is ready to ship. Could be zero inventory as suggested.

 

GM changed up the part numbers and such. They still make them in this new form with a new part number. And yes the prices have gone up quite a bit. Jegs says ready to ship same day:

https://www.jegs.com/i/Chevrolet-Per...91673/10002/-1

GD

 

I went looking for those and the search was empty. Well nice to know it's available but at that price(ouch) at this time, I'd still look for a good used one. If they were nonexistent in yards then maybe but maintained 150k used one wouldn't need anything but gaskets and valve springs. They're still trading hands $800 and often less.

 

Just find a roller 350 block and refreshen it up. Find a local machine shop if you can.

you basically want a bolt on tuned L98. 87 oct? No more than 4500 rpm? Idle and drive well? That is about all you can do, maybe a mild 212-218 cam and call it a day after tuning. Put a good converter in it. Have fun

vortecs are nice but prone to cracking if you are looking for a used motor. Plus the cost of tpivortec base if they still sell it is high and not worth it imo

 

machine shop costs, cam cost, intial block and head cost all probably outweigh the cost of a running vortec and base. Not to mention more hassle of a refresh, hoping the machine shop doesn't suck, and then being saddled with inferior heads. While a viable option for the OP, it's not a choice I'd personally do....again.

 

Ive often wondered how much difference an L05 equally cammed and L98 would be running on TPI. I know the swirl ports aren't optimal but honestly TPI is a lower RPM setup in itself and swirl ports make power at low rpms? You can get L05 engines around here almost free as I picked one up a while back running for $50. Those old engines ran forever and were reliable.

 

I had this setup in my GTA. Previous owner replaced the motor with a reman crate engine. When I pulled it and tore it down years later, It was a 350 with swirl port heads and an L98 cam. It ran pretty good, lots of torque, but seemed run out of power even earlier than a typical L98. I dyno’d it once and it did 198hp @ 4000rpm at the wheels. Only mods were a Magnaflow cat back and on open element air filter in place of the airbox. Would have been a great truck engine.

I also found that with the stock ignition timing it was prone to detonation under heavy load on the 2-3 upshift and would not pass emissions due to high nox. Retarding the base timing a few degrees seemed to help this. At the time I couldn’t figure out why, but after tearing it down and finding the swirl heads, it makes sense. They have a faster burn, so they require less timing.

 

I guess for someone needing something close to a STOCK L98 then an L05 crate wouldn't be a terrible replacement if you swapped in a cam close to the same specs and ran 6deg timing on the engine. I think the L05 crates Ive seen are flat tappet engines but they seem to hold up. I think only the Caprice and Cadillac L05s had roller cams IIRC.

 

How many bucks would the budget be?

 

you gamble on a junkyard take out as well... esp with vortec headed motors. you have to do your homework and hopefully get fortunate enough to have a good shop around that can handle what you wanna do. If not then you gamble or outsource and pay more for shipping in a crate

if you can find a L98 from a vette or camaro that be the way to go. Just freshen it up. Rebuild heads, inspect bottom end etc. can cost more but atleast its done right and you get what you need

if you can find a good condition L31 have at it. Great heads if they aren’t cracked


i would never run a flat tappet with todays oils and having to mess with additives and cam break in. Retrofit roller if you have to if you cant get a roller block

 

Besides the budget question asked earlier, how does used and then refreshed vs new stack up.
A new L31 from GM is $3200. Free shipping too.


Add to that the Vortec base. 300?
Now, a junkyard engine that needs the full Monte. Next oversize bore. Maybe just a polished crank (no machining). All the other machine shop incidentals. Plus parts. Maybe an oil pump. Timing chain. Distributor. And this is on the assumption the heads are OK. Or go for an L98 but the same scenario applies. Where are we at?

 

I went the route you suggest myself. Found a good L98, had heads re-worked and freshened up the bottom end. I may have as much in it as a crate but its exactly what I wanted for a good driver.

 

This is the route I took last November, although I paid $1,949 (plus tax) shipped; they have gone up in price significantly. And if you want to stay with TPI, the SD vortec intake manifold is $400. FWIW, everything else from my 305 bolted up to the new crate L31.

 

Someone mentioned remanufactured...

 

Item 1 on my list needs to change. "1. Must use the factory TPI" is proving to be really restrictive based off the information presented and some additional research.The L31 heads are on my list. I will list some of the sources I have been looking at as well. Now granted, i know some of the motors in these dynos and other tests are 383s or 350s with some other flavoring (Compression, connecting rod length, ect, but either way it shows the characteristics of the power curve of the TPI system.

Extrude hone at 4:13 in the video is interesting.
Across his dynos I see that a bigger throttle body is a necessity as well as bigger runners. I see that the shorter the runner is the further out it pushes your power band as far as RPM's is concerned. Short tube runners are out of the question. It also looks like most of the systems in the "Mid" range extend too far out of my RPM range.

Interesting article from online

https://www.hotrod.com/articles/hppp...-block-engine/

I am convinced I will be swapping to the 350. While the blocks are nearly identical, the 350 is better able to utilize the air flow in the upgraded components. Not to mention parts are readily available with far more options for the 350 components when it comes to pistons ect.
383 seems to add a lot of expense for not a lot of gain in my application so I would probably axe that. The longer connecting rods are interesting but I start to worry about my compression ratio.
These are the guarantees as of this point. Still not sure on the specifics of what exact make and model of each component but I am seeing the restrictions that need to be removed. I am willing to start with a block and add components from there.
Vortec heads are happening.
A new cam is happening.
Exhaust Headers are happening.
Larger throttle body is happening. (58mm)
Larger runners are happening.
New better flowing intake.
700R4 is getting beefed up
Will be stiffening up the car.
Upgraded brakes will be required.

As far as my budget goes it is just a matter of time as time is hours at work which is money. I just want to do this once and do it right where I will be happy with it. My wife and I have dated in this car and I have had it since I was 18. That was 12 years ago. This car is not getting sold (The wife agrees). This car is my project until I lose my wits or my heart beat. So I will dump as much money as needed to do this right. I am a practical person and would prefer to do this for only as much money as is necessary (research and others experience should help with this). This car might see an SCCA course once or twice a year for fun or even PIR if they have a track day but it is for fun only, and not for competition. I would throw it at Beaches Wednesday night drags once for the experience and just to see what the car will do. But that is the extent of what this car would be put through besides driving an enjoying it on the road (trips out to the beach through the windy twists, highway on-ramps, and just making it a car with more personality than what it has right now ( has some already but making it feel like the muscle car it wants to be.

 

Doing some research now on the edelbrock intake vs Hiflow edelbrock, and the SDPC intake. If there are anyother competitors for intakes let me know. I am hearing good things about FIRST. Point for the FIRST setup is that it looks like a beefed up factory setup... Sleeper aspect is fun.

 

https://firstfuelinjection.com/tech-support

Finding good information on the FIRST system here.

 

I have the FIRST intake and it's excellent.

Here's my build:

https://www.thirdgen.org/forums/tech...uild-dyno.html

The FIRST can be used on traditional or Vortec heads. I'm in the process of switching to AFR's and expect to easily hit 350 at the wheels. If you are sticking to Vortec heads pay attention to the cam profile I used. It's excellent for Vortec's.

GD

 

I read through your thread GD. Good information. I will never be able to use AFR 190s with what I am planning but the AFR 180s are interesting. Going to do some comparison on the l31s vs AFR 180s.
So far I like what I see on the targeted RPM range for the AFRs. They seem to outflow the vortecs and would still work with my application. Some other bonuses are that most flow improvement has already been done to the AFRs. That is cost I would have done on the vortecs to upgrade them to the same level. I think I'm sold on the AFRs and the FIRST intake. Still not sure on a cam yet but this is exciting for me as a plan is coming together.

 

AFR makes a nice Vortec head as well. I considered them but the 195 is has a slight advantage.

GD

 

If there's a choice to be made between the Vortecs and AFRs, and there nothing invested in a Vortec specific manifold already, I'd side step the factory heads. As mentioned, getting the Vortec up to speed takes some bucks unless, as I did initially, you can make do with the out of the box version. Otherwise it's springs, retainers, screw-in studs (with or without guide plates) and then the economy goes out the window.
One thing I've observed is that AFR doesn't tend to publish flow data below .200". While I don't expect huge differences between the two heads in question, it's the low lift flow that give the Vortecs their credibility. Particularly just of the seat @ .050-.100".

 

The FIRST manifold can be drilled for both patterns. I don't believe there was any cost associated with it either. That's what I had Ken do because I was speculating I might want to step up to the AFR at some point. Happened sooner than I anticipated.

GD

 

Similarly, but in reverse, my RHS Pro Torker heads are factory drilled for both conventional and Vortec manifold patterns. That said, I've always understood that the Vortec intake port doesn't align nicely with a traditional manifold. Something I may have to deal with if I decide to change to a single plane intake. There are 8-bolt versions out there but the resale market tends to be ripe with 12-bolt Super Victors.

 

AFR 195cc from their website.
Street Head Flow Chart
.200.300.400.500.550
Int146 201 247 275 280
Exh119 166 197 213 218

Lift (in.) Intake (CFM) Exhaust (CFM) Exhaust w/ pipe (CFM) 0.100 70 48 49 0.200 139 101 105 0.300 190 129 137 0.400 227 140 151 0.500 239 147 160 0.600 229 151 162.
(Will organize this better when I get home from work. Hard to do on my phone.)
From l31 coalition.

At .200 and up the AFR flows better.

 

Typical of AFR not to post their below .200" numbers.
As for the AFR 180s,


That list is from Stan Weiss' website. You may find some interesting reading there.

http://users.erols.com/srweiss/tablehdc.htm

 

Plenty of L31 data although you have to watch for the testing methods. Particularly the fixture bore size used. 4.03" vs 4.10", etc.

 

The FIRST manifold is primarily designed for the pre-87 bolt pattern heads (which is why I got the AFR 195's because if anything, it will fit better). But has the ability to bolt and seal to a Vortec. Any port misalignment (I'm sure there was some) was not noticeable either during assembly or on my dyno numbers using stock Vortec's. I think the variation is minor.

As for the low lift flow on the AFR's..... if it is in fact worse than a Vortec it doesn't seem to show up in any of the dyno charts comparing the two that I have seen. They seem to act almost identically till you get up higher in the RPM where you need that extra flow and then the AFR's just keep climbing while the iron Vortec falls off.

AFR is also now selling "budget, as-cast" versions of their heads - without all the CNC porting, etc. They are inexpensive and outperform a Vortec easily.

https://www.airflowresearch.com/195c...cylinder-head/

$477 each fully assembled with the same high quality parts used in the CNC versions. That's insanely cheap.

GD

 

Thats because low lift flow isnt the end all be all way to do things and doesnt always dictate how power is made.

afr’s are known to be higher velocity heads and have efficient chambers. They do well out the box and for race applications do better once cleaned up for a better velocity profile to suit high rpm engines

another advantage to afr...aluminum heads are 50 lbs lighter Than iron. Thats significant in itself

 

Just to set the record straight, I'm not proposing that the Vortecs are better than the AFRs. That the AFRs doesn't post flow data at .050" is because they don't care. They don't have to care because they have a superior cylinder head.
Fair enough?
What I AM saying is that, for a fact, the higher flow below .100" most certainly contributes to cylinder filling at lower RPMs. And I can't recall ever seeing a dyno graph that starts off idle.
I'm not talking about outright power production.
AFR doesn't care because nobody cares about lower RPM efficiency if they have heads designed to make power to 7000 RPM or more. Simple way to look at it really.
Now, that said, if I were to be designing an engine that saw a max RPM of 5000 and was purposely built as a tow truck engine, then I wouldn't waste my money on a high zoot head and I'd drop a set of box stock Vortecs on there, cam it appropriately and call it a day.
As for the weight, well, that goes without saying. I'd like to have aluminium heads myself but for whatever reason I ventured down this cast iron path and even stuck with it for round two. And three.
Live and learn.

 

Irregardless of a 180 or a 195... I'm wondering if it would be effective to make the hood louvers functional with a ram air set up. Blowers and turbos are not my kinda thing but they have their place. That should help feed the heads. I'm guessing it won't provide a ton of air as those louvers aren't exactly a big blower sticking out of the hood but it would be something I would think... This calls for research... To the batcave!

 

I think at this time we have reached a point where the stock Vortec's are all 20+ years old and the AFR "as-cast" Enforcer heads are now at a price point that even if I were building a tow-truck engine I would probably just buy the $477 budget AFR heads and call it a day. That's less than $1k for pair. A set of remanufactured iron Vortec heads probably won't cost significantly less in the grand scheme of an engine build and if you have to pay for shipping that 50 lbs makes a heck of a difference as well.

GD

 

Check this out Batman!

 

Won't make any significant difference. Sounds good on paper but the reality is it's just not worth any performance. You are talking about TINY gains at high speeds.

GD

 

Check this out Batman!

https://www.thirdgen.org/forums/fabr...ir-intake.html

 

Yes sir. Times have changed. My 1st Vortecs were purchased 20 years ago. To start again, I'd pass them by and certainly start with the lightweight alloy. If not the newer AFR, then maybe some of the now much better offshore castings that come this way.

 

Most of the places like Hawks third gen that are claiming any gains from the ram air set up are using a stock 305 anyways. So my thinking is since the stock 305 flows so badly that is the only reason they had gains... Marketing at work I see... I think you are probably right about the ram air GD.

 

Chad Speier might argue otherwise. He's shown his work on the flow bench and backed it up with real world data. And his engine is no slouch either.

 

Do you have a link to the data skinny? I would love to look at this information.

 

Post 44 above.
If the link doesn't work I'll dig it up and repost.

 

Correct. Ram air if done right will make a difference. We seen over a tenth in et closer to .15 i believe on a 530 whp 416 ls3 car. I’ve seen about the same on my bolt on ls1. Its beenproven to work on 4th gen ls cars with lids. Chad’s tpi intake mods certainly helped as evident by his kpa readings

i myself did not see any gains going to a custom 3.5” maf and cold air intake pipe on my 383 vs the tpi snorkel intake with ram air ducts to the grille with stock diameter but gutted maf. I think its worth the effort