I've searched a lot and cannot for the life of me find a specific answer to my problem. I have a 1986 trans am with the 305 TPI and I want to swap in a 383 stroker with aftermarket TPI upgrades, but I can't find a definitive answer on whether or not I can use the existing harness in my car already. To clarify my exact plan as far as what block I'm using, I'm planning on getting a 350 core and building it into a 383 TPI. I've looked for blocks to start with but I can't ever get enough exact information on it to suggest that I would be able to use the existing wiring harness. Now, I've been able to find 3970010 castings, specifically a 1979 4 bolt main out of a 79 camaro for about $100, but as I explained, I'm not sure if the old harness would work. This is my first car and first time building an engine, so I don't know much if anything. I'm aware this is going to be slow and tedious but I'm prepared for that.

For those who will inevitably ask about budget, I don't have a set budget but I'm not looking to break the bank, as I'm a college student home for the summer/winter breaks. As far as the goal for the car, I'd like a powerful daily driver.

Thanks in advance

 

I would probably source a later 880 block. Invest in a good cam and roller lifters.
The harness can be reused but you will need ecm tuning .

 

Thank you so much, it feels great having a starting point now.

 

What I'm about to tell you is not to brag, talk you down or be an a**
Just food for thought before you dive head first into your endeavour

I wish someone would have told me a few years ago!!!

A)
"I've searched a lot and cannot for the life of me find a specific answer to my problem. I have a 1986 trans am with the 305 TPI and I want to swap in a 383 stroker with aftermarket TPI upgrades, but I can't find a definitive answer on whether or not I can use the existing harness in my car already."

If you swap a SBC 383 for your 305 '86 TPI, it will fit. HOWEVER:
-Need new custom exhaust and headers to fit new heads and match engine HP. OEM will choke it. It can be very expensive.
-If you reuse the OEM TPI (TB, plenum, runners and intake), you'll choke the hell out of your 383. Need full aftermarket system.
-With and aftermarket TPI intake, you have to delete 9th injector and maybe EGR
-ECM controls timing, so you need to reuse HEI GM ECM controlled distributor
-Knock sensor and knock control module are different for a 350. Even if you swap, it might cause problems on 383
-OEM air intake will restrict flow. Unfortunately, the MAF is part of the track and is restrictive for a 383.
-AIRS need to be deleted
-EVAP is ecm controlled
-Need new injectors to match new HP
-Need custom fuel lines from OEM GM solid lines to after market TPI fuel rail with adjustable fuel pressure regulator
-OEM cooling system should be sufficient if it's for a daily
-All accessories should bolt on new engine

Considerable issue:
Your '86 TPI is a '7165 ECM with a $32 mask and MAF. So in theory, you could upgrade to a $6E mask and keep the same wiring and ECM. Issue is, the MAF is restrictive. So you would need to switch to '7130 ecm with $8D mask and use a MAP. In this case, existing wiring won't fit. There is also a possibility to modify '7165 to accept a MAP (look-up TGO, there is info on that).

And finally, you will spend countless hours trying to dial in the tune!!!!!! Good luck with that.

It's quite the endeavour for a college student... and can turn into a money pit nightmare

B)
You also need to upgrade brakes, transmission, rear-end chassis and suspension... believe me.

C)
"As far as the goal for the car, I'd like a powerful daily driver."

What a classic line? We hear it all time on TGO.

What is a powerful daily driver? Nowadays, a grocery getter sedan has more than 300hp with all the amenities you can ever imagine, powerful brakes, good handling and comfort. They can do 1/4 mile under 14 seconds easy and blast through 0-60 with modern traction control and transmission. A clunky '86 Firebird with a hacked 383 stroker, loud, annoying, with no brakes, no traction and flexing chassis is no match. All you'll do is spin tires and get laughed at... unless you really put the resources into your build.

GM did not build these F-Bodies for performance. I repeat, GM did not built these F-Bodies for performance. They are relics from the past, obsolete. To turn them into "powerful daily driver", you need lots of resources.

You want to daily it? I suggest you keep it stock, save your money and enjoy it.

Why do I tell you all that? Well here's my 383 swap: https://www.thirdgen.org/forums/engi...st-intake.html



Lots of resources when into into and it's not something I would daily drive. I prefer my bone stock IROC-Z as nice cruiser on sunny day.



But for a powerful, inexpensive daily driver, this is what have:







Cheap, just a few mods and I get 13.8s 102mph on quarter-mile. However, it's due to lack of traction at launch. On a rolling start, it's a rocket with lots of mid range torque. It does 150mph electronically controlled. I track the damn thing and get outstanding results for this kind of sedan. Ventilated seats to keep me cool. Once off the track, adaptive cruise control, good fuel economy (28mpg combined) and quiet. I drive it in all weather and on dirt roads... I don't care. All this for $25,000 including mods, wheels and tires for track + track brake pads.

Food for thought

Peace

 

Please post a pic of your Trans Am

Thanks

 

 

Wow that's a lot of info to take in, thank you for that. To be honest, I got kinda lost at the ECM stuff, and I don't really understand it that well. Looking back on the "powerful daily driver" part, I realize that's not a great description/help. To give a little perspective of my personal situation, this isn't my only car to drive, so if it's down I don't have to bike to work or anything. Another thing is, I'm almost 19, and this is my "fun car" essentially if that makes sense. My idea is that I enjoy this car to the fullest while I can still spend money on it before I have to start worrying about houses, paying off college loans, and other big bills. I'm not afraid of doing work to it or it being out of commission for a while, since as I said, I do have other family vehicles to use.

That said, I'm not hellbent on a 383 or swapping in a different motor, meaning I'm not just going to do it no matter what. I'd like some advice as to what route I should take for power, whether that be rebuilding my 305, swapping for a 350, 383, etc. Also, when I do the power "mods" I'm looking to do them one thing at a time (i.e. building/swapping the motor, then exhaust, then transmission, etc). For the question of "how much power" I'm mainly just looking for something that will not get walked by an Acura TL while under WOT lol. I'm not looking for a 700+ HP build, I know those are unreasonable unless the motor is practically dying at idle and will inevitably be a gas guzzler. I'm looking for something maybe around 300-400 HP, if I understand numbers correctly.

From what I can understand, the list you gave covered all the bases, but I'm just not able to understand it all. I'm not looking for someone to hold my hand and walk me through everything, but I would appreciate some help navigating all the information about modifying an engine, or even just how to make sense of it all.

As far as pictures of the car, what are you looking for? The engine bay I assume, maybe the underside/trans tunnel?

Thank you for the information.

 

Hey icedog,

SbFormula has some solid advice. There is a lot to go into engine swaps with these platforms. This is especially true to ECM/PROM tuning. Nobody messes with these cars anymore and an engine swap would require a tune. If this is something you would like to do in the future, I would highly recommend reading these forums and reading up on some of the tuning information. Personally, I converted my 89 Bird to the DynamicEFI EBL FLASH II ECM. It converts the MAF setup to speed density and is super intuitive and user friendly to tune once you do a little research. Understanding the basics of ECM tuning is detrimental to an engine swap.

Do yourself a favor and play around with this kind of stuff on a stock engine and upgrade everything else first. This means brakes, suspension, rear end, and transmission prior to adding a larger engine. You'll thank yourself later. Everyone (including myself) loves to start modifying the engine until you realize that every other component on the car is not up to the task.

There are plenty of people on this forum that have done similar builds and and all here to help.

-Tyler

 

Icedog, I did a TPI conversion on my 87 Monte Carlo SS several years ago. I went with an 87 ECM harness and 7165 MAF ECM. I have been tuning with TurnerPro since the install. I do not use the cold start injector which I eliminated. My actual programming is 89 TPI which does not have the cold start injector. For your 383, there are posts on the forum that highlight the changes in programming that will be needed, just google it. I have found several posts on this forum for 383 TPI programming changes. I am also planning to do a 383 install, but with the Holley Stealth Ram. Get a GM shop manual for your car and the TPI system that you plan to install. That will help allot.

Good Luck,
Fred

 

I would do the 383 and a standalone EFI system. They're pretty easy to install and will flow much better than a TPI. Modern EFI is far more easy to adjust and not that expensive. You would need an EFI system and a fuel system. Most come w either a vortec or old school sbc intake.

 

I did exactly that, except I went the hard route of my own tuning with '7730 and S_AUJP... I mostly have over 1000 hours into that alone!!! Did lots of experimenting on the LB9 first. 383 swap was the last piece.

Here's a good book:

 

What he is referring to is the mask (tune nomenclature)
'86 to '89 where MAF TPI systems but they used 3 different tunes: $32, $32B and $6E. $6E was used in 1989 when they did away with the cold start injector. You will need to do a lot of reading to familiarize yourself with this ECM and tuning stuff... Lots to take in.

 

Wow thank you all for this information, it really means a lot. If I'm understanding correctly, the best route for me at the moment would be to "experiment/learn" or modify my LB9, then later down the line worry about a bigger engine and more power. Due to the drivetrain/frame needing to handle the power, but also because that's a big undertaking and a lot more money than I originally thought it would be. Again, if I'm reading this right, to modify the LB9, I would only need to worry about the engine components themselves and the ECM tune and not the entire ECM?

Thanks guys.

 

In a nut shelL, yes!

Modifying the LB9 can also be expensive to gain 20-30WHP. I'm talking the usual bolt on stuff: cold air intake, air foil, headers+exhaust with tune. IMO, it's not worth the money and annoying exhaust drone. It might have been 2 decades ago, but nowadays, it's not much HP gains. Besides being louder, you won't go that much faster and you will get blown in the dust by Civics and Pick-up trucks. Lack of traction and drivetrain flex will hurt it. Wheel hop can be bad on them F-Bodies!!!!

Be careful with what you read on TGO threads. Always look at the date. Some stuff is close to 25 years old!!!! Taking an LB9 from 225hp to 265hp was kick *** in late 90's early 2000s. Nowadays... expensive and laughable. Times are changing.

 

There are stepwise thresholds where the car needs another batch of upgrades to support the power, and crossing these thresholds means more $$$$. 350 Hp is a sweet spot where the car is more lively but isn't breaking too much stuff. Things like transmission and rear axle start to have issues around 400 Hp, and are big dollar items to upgrade. After that, you'll be focusing more on suspension and chassis upgrades to make the car predictable under heavy throttle.

Getting a strong SBC combo to fit under the stock hood can be a real challenge. Most the EFI intakes have big compromises in the power curve. And the really good "carburetor" style intakes tend to want to poke through the hood. There is a guy here by the name of FJA1791 that has an incredible car that runs mid 10's and everything fits under stock hood. I would try to find more information about his setup.

 

This is a 450hp/tq 350. It fits under the stock 82 TA hood. It's a pro flow xt. It rips and was pretty easy to install. The pics are while it's in paint. The hood closed fine. There's even room for a torque storm blower!

I agree w all the comments about the drivetrain and most intakes. I needed a hood scoop for the old 4 barrel style pro flo. This set up is tight but fit.

 

We're twinsies with red 'Birds and ROH RT wheels from the '90s

 

I noticed you had those on your car in a pic the other day. I have 2 sets. A set of silver 17x9s and a mat black 18/10 and 18x9. The silver ones I got around 2001. The black set I go from the same place last year, Group A wheels. They had new old stock. I needed wider tires in the rear. I had them powder coated to match the mat black/satin parts on my car. I love these wheels! They fit the look of the car so well.
I got this pic yesterday, they're covered in body shop dust but you get the idea.