joey 350 LT4

so my current car is a 91 1le formula. current mods include 6-speed trans vortec heads 1.6 RR close to 500 lift cam arizona speed runners and TB eddlebrock vortec base 24 lb injectors msd dizzy. essentially a well built TPI. other then sometimes has idle issues and its been sent out for a tune..

i am curious as to what u think about my next step id like the car to have a bout 400 rwhp and a daily driver. ive looked into my options for the ls1 swap.. but i was thinking about maybe a rebuild on the TPI get a better rotating assembly and maybe goto a 355 do some head work and a few other things and get the EFI connection 24x set up.. do you guys think thats worth it or maybe like an lt1 swap?? i do have the tranny for it so id save some money.. just wanna know what you guys think thanks!!

torque_is_good

Any path can get you there. None will do it with a stock engine.

before going through the obligatory hypothetical discussions, the first questions can only be answered by you.

A: are you comfortable buying and then installing a used engine with an unknown disposition despite the claims of the seller? It's only known if paperwork backs up the claims

b: how long can this vehicle be off the road to complete the project?

C: what are your own personal capabilities and workspace and tools? Despite the asurances of your friends, you'll be doing the lions share of work yourself.

D: are your expectations to have a reliable engine once it's installed? Or, are you OK gambling and buying a used engine?


E; have you ever driven a vehicle with 400 RWHP? How about even 300 RWHP?


F: the biggest question of all. How much money beyond $3000 do you have available TODAY because you said 400 RWHP and you ain't getting that with a junker nor cheaply.

I don't know the condition of your present engine but that will be the least expensive path (LS1 and LT1 will need top end work but both are used engines as your starting point unless you rebuild them)unless you can find a crate engine at a blow out sale. You want 400 RWHP. That is not easily done without spending money.

cuisinartvette

400rwhp with a TPI
Little bit of a lofty goal. How bout rwhp in the 3xx with 400+-rwtq that would be more feasible and affordable.

Making an honest 400 at the tire takes more than most think. with a TPI lets say forget it in most cases

joey 350 LT4

awesome ok in order

A.that is one of my worries and being in jax fl getting lt1s are easy but still pricey

B. comfortably 3 days but time isnt to much a big deal

C. i have all tools necessary except major fabrication tools but can be acquired and if need be i can use a lift. and i have done several motor swaps none of the lt or ls or custom harness work.

D. yes reliability is my main goal hence my current issues with the old prom ECU. i am looking to be able to drive to an autocross track and back not that i will but thats how reliable i am looking for.

E. yes i have had my first 89 firebird dynoed at 379 to the wheels an 85 bird that was 578 on a 175 shot and i have owned a 98 ls1 and a 94 25th ta.

F. money isnt to big of a deal plan on getting parts one buy one.


i personaly love the idea of a TPI capable of taking an ls1 down but so far i am least experience with the older motors and find my self more comfortable with lts and ls.

i have seen 400+ out of a tpi gm hightech did one but its a lil more then i plan on doing. i just wanted to see what ppl thought of sticking with the old TPI or if everyone was gona tell me to just go with the ls1

lets say realistically i can get 375 hp and 425 ftlbs out of a TPI with great reliability would you think the cost of such is worth it compared to and lt1 swap.?? also assuming i would rebuild the TPI from head to toe "work" the heads get a new cam and do the 24x conversion. also any ideas on changing the whole rotating assembly? thanks guys!

torque_is_good

then as you know, air/fuel and combustion are the big issues.

A 350 is a 350 or a 355 is a 355 or a 383 is a 383, you get the idea.

The LT1 is better suited for high HP than a TPI based induction. The LS1 is even better suited because the induction/injection is better but the heads flow better.

Since you are in FL ( go Jones-Drew) we can convert and not worry about smog etc. You could shop around for a 383 crate with better heads and intake/carb than what the TPI could do.

if i was going to do that much work, I would not drop in a used LT or used LS. I would buy the powertrain with the intent of a complete rebuild and unless you wanted to spray, either plant would be Ok on the bottom end but you are at the edge with the LT.

edit: 3 days!!! you are a miracle worker. I'm in Sarasota county (west coast) FL and I had to shop around to find machine shops with reasonable prices. I went to the next county to the south. You might have to do the same where you are, or even head north to GA. I saved $300 on my tranny rebuild and $700 on the engine work and that was 2 months ago.

five7kid

iTrader: (14)

Unless you have the "Overhaulin'" crew at your disposal, don't count on it.

I had everything pretty much laid out, still needed to take vacation time to get it running. And that didn't include exhaust.
https://www.thirdgen.org/forums/ltx-...p-17-days.html

1989GTATransAm

iTrader: (3)

To make 400rwhp with TPI you will need after market parts along with welding and porting capabilities. It is all about airflow. The TPI cars that are close have ported aftermarket heads or AFR 195's. Either a custom cam or something along the line of the Comp XFI 230/236 @ .050" cam. Heavily massaged TPI systems. I mean heavy. Here locally in SoCal we are running Dyno Don short tube headers and exhaust systems along with 3 1/2" cold air intakes.

We are having a dyno session on March 26 and I fully expect a few cars to finally exceed the 400rwhp mark. One will be an A4 and hopefully if I can get the runners done on time for one of the cars it should be over 400rwhp.

It is an easier path with the LT1 and the LSX motors.

joey 350 LT4

i deff appreciate all the input. and 3 days would be for just doing some work on the TPI. motor swap would take alot longer haha and for me all the wiring and i hate wiring.

so lets say i go with a rebuild and bore it over head work and a good custom cam and a 24x ls1 ecu conversion. anybody disagree and think getting an lt1 is a better way to go? mind you i can find alot of those cheap i do have access to some 5.3 and 5.7 ls motors not complete tho.

im thinking the easy rout is the work with wat i got vs finding all the good deals on some lts??

torque_is_good

cheap motors are easy to find. Do you want a reliable engine? If so, then be it an LT1 or LS1, if you find one for $700 including computer and harness, you then need $2,000 to rebuild the engine. Do you really think an excellent engine sells for under $1k? But, a top end kit for the LT1 from AI or lloyd are around $1500. Then you need new injectors and should rebuild the bottom end.

oops, maybe they do, here's a "strong" 350 from craigslist that only needs an oil pump. Just because he replaced the engine with a crate motor vs rebuilding this 350 doesn't mean anything. The engine is "strong". The guy is only asking $300. Why did I bother rebuilding my 305? I could have had a "strong" 350

"I have a chevy 350 that's been bored 40 over. It's a good strong motor that was takein out of a dayly driver it's was gonna go in my mud truck but I changed my mind, now I just need to get rid of it as soon as possible! IM MOVEING! Hense why the price is so low...
The motor is pretty much complete. I just took the sensers off it to put on the crate motor that replaced it
But like I said it's a strong running motor it needs a new oil pump witch is like $30 "

Artisan

If you want to go with a TPI the 383 is a great base engine. I would look at a FIRST TPI. A decent cam, a set of Don's Headers, A Great set of Heads flowing 300 cfm, I suspect you will be very close to your goal.

joey 350 LT4

i will deff use all the advice guys and let u know how it turns out!!