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89 350 TPI Replacement/ Crate engine options

Old 11-28-2018, 07:14 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Seeing as how the L31 is the same engine aside from the camshaft as the Ram Jet and the 330hp 350, the engine is cable with a cam change. The biggest problem reaching 330-350hp with your plan is the stock tpi system. Put a stock TPI system on the strongest 350 and it's going to choke it down. That's TPI for you.
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Old 11-28-2018, 07:36 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Ok so the Ram Jet Engine comes equipped at 350ish HP?
And yes from my reading I see the TPI chokes off HP. Iíve been looking at the First TPI system. Looks expensive but I havenít priced one yet.
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Old 11-28-2018, 07:46 PM
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Re: 89 350 TPI Replacement/ Crate engine options

My son and I have been researching, and found very little solid information. Our best estimates are with an L31, and TPI, around 300 horsepower, and approximately 400 foot-pounds of torque, with an even broader, flatter torque curve.

It should move a thirdgen very nicely, and much better than stock,
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Old 11-28-2018, 08:51 PM
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Re: 89 350 TPI Replacement/ Crate engine options

My son and I have been researching, and found very little solid information. Our best estimates are with an L31, and TPI, around 300 horsepower, and approximately 400 foot-pounds of torque, with an even broader, flatter torque curve.

It should move a thirdgen very nicely, and much better than stock,
It's been a few years since I researched it, but I would've said about 275 to 300, so I'd say you're about right. I've always wanted to build a budget vortec TPI. L31.....slightly bigger cam....basic "stage 1" porting work, smooth the casting, port matching etc. etc. but not go crazy, stock TPI, and really see what it'd do.

.....as for the TPI choking down power, keep in mind that for a mild 350/stockish type build, I really feel that any loss of dyno'd horsepower is made up with daily driven useable power band. Meaning it's very fun, and torquey.
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Old 11-28-2018, 09:55 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Oh I'm not saying it wouldn't be fun to drive. I'm saying if you go into it thinking you're going to get 350hp on the dyno, or be pissed off, don't blame me when you're disappointed.
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Old 11-29-2018, 02:25 PM
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Re: 89 350 TPI Replacement/ Crate engine options

given the apparent healthy demand of vortec TPI basis, you'd think there'd be dyno charts out there...
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Old 11-29-2018, 03:13 PM
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Re: 89 350 TPI Replacement/ Crate engine options

given the apparent healthy demand of vortec TPI basis, you'd think there'd be dyno charts out there...
...I think a lot of guys just wanna build and engine with some parts they have (vortec heads) and give it a little more oomph than stock. Lots don't care about the numbers.
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Old 11-29-2018, 04:03 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Originally Posted by Abubaca View Post
...I think a lot of guys just wanna build and engine with some parts they have (vortec heads) and give it a little more oomph than stock. Lots don't care about the numbers.
I hope that's the case, and not being facetious, it isn't that the numbers are a bit too sobering

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Old 01-27-2019, 11:13 AM
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Re: 89 350 TPI Replacement/ Crate engine options

Hey guys, I'm going to piggyback off this forum... I've got an '89 Trans AM GTA just picked it up yesterday for pretty cheap. It has a spun bearing so I've been looking at replacement options. Based on what I've read so far, it sounds like the L31 paired with Vortec/TPI Intake base (links below) are the most straight forward to swap in and get her rolling down the road again. It doesn't look like this forums OP is still active, anyone have any further advice for this setup? Looking at making a purchase within the next week or so. Thanks!

https://www.summitracing.com/parts/n...display-detail

https://sdparts.com/i-23896057-sdpc-...SABEgKtA_D_BwE

-RtR
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Old 01-27-2019, 12:45 PM
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Re: 89 350 TPI Replacement/ Crate engine options

I just finished the L31 swap with the Vortec baseplate and it is pretty straightforward. One other thing to watch for is that the L31 is made to work for several different vehicles so it has spaces for sensors that our cars don't have. One example is the crank sensor. The holes for these sensors have to be capped off, just another thing to remember when fitting things together.
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Old 01-27-2019, 01:48 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Tilly, Thanks for the confirmation and appreciate the heads up on capping. Btw, did you do a new crate motor or snag one from a used vehicle? If you did the new motor, do you mind sharing where you purchased it from?
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Old 01-27-2019, 02:44 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Did you buy the red GTA from Raleigh? I’ve been looking at it on Craigslist a while thinking it was a great deal. Warren engines in Clinton has great deals on L31 engines, I’ve bought a couple of L31s and other sbc’s. Check out their website, the best prices I’ve seen locally.
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Old 01-27-2019, 04:28 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Thanks Ty! I'll check them out. And yeah it was the red one on Raleigh's craigslist. Really solid body underneath and only a couple minor rust areas throughout the rest, which is what sold me. Plus the final price left some breathing room to find a new engine.
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Old 01-27-2019, 04:48 PM
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Re: 89 350 TPI Replacement/ Crate engine options

I got the crate motor from Jeggs. Hope everything goes well with your ride!
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Old 02-03-2019, 03:51 PM
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Re: 89 350 TPI Replacement/ Crate engine options

We just bought a l31 from a Chevy dealer in Fredericksburg Virginia for 1745, free shipping and received a 100 visa gift card with purchase. Best deal I could find on the web. Comes with a 1 year warranty ( 3 year if it goes in a 3/4 -1 ton truck). Although Iím sure my warranty will be void after I put the 113 heads on...
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Old 03-25-2019, 05:25 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Originally Posted by Oilburner View Post
We just bought a l31 from a Chevy dealer in Fredericksburg Virginia for 1745, free shipping and received a 100 visa gift card with purchase. Best deal I could find on the web. Comes with a 1 year warranty ( 3 year if it goes in a 3/4 -1 ton truck). Although Iím sure my warranty will be void after I put the 113 heads on...
Got more information on this dealer? Cheapest I am seeing is around $1900.
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Old 03-25-2019, 08:09 PM
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Re: 89 350 TPI Replacement/ Crate engine options

I believe the name was Radley Chevrolet. Iíll see if I can dig up my invoice when I get home.
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Old 03-28-2019, 09:22 PM
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Re: 89 350 TPI Replacement/ Crate engine options

the stock l31 with the camshaft from the sp350/357 vortec(also simply add ls6 valve springs and comp retainers)
will give you 357 horsepower and 406 ft lbs.its cheaper to buy the l31 crate motor and stab this cam in yourself and save $1500

i just bought a used(but extremely clean and great running) l31 and this cam myself and im gathering up the specific parts to swap it myself as well.
ls6 valve springs are $100 on s u m m i t and the retainers are under $100 canadian,25% less for americans(lucky stiffs)
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Old 03-29-2019, 02:12 AM
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Re: 89 350 TPI Replacement/ Crate engine options

Not sure what the lift of that cam is but if youíre trying to squeeze what you can without machine work, also get the appropriate keepers/locks. I saw a c0.03 increase with some comp keepers over stock l31 ones

some have also got extra lift from different valve seals


Originally Posted by 1986BANDIT View Post
the stock l31 with the camshaft from the sp350/357 vortec(also simply add ls6 valve springs and comp retainers)
will give you 357 horsepower and 406 ft lbs.its cheaper to buy the l31 crate motor and stab this cam in yourself and save $1500

i just bought a used(but extremely clean and great running) l31 and this cam myself and im gathering up the specific parts to swap it myself as well.
ls6 valve springs are $100 on s u m m i t and the retainers are under $100 canadian,25% less for americans(lucky stiffs)
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Old 03-29-2019, 12:15 PM
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Re: 89 350 TPI Replacement/ Crate engine options

I just picked up one of these
https://www.summitracing.com/parts/nal-12670966
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Old 03-29-2019, 12:36 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Seems a bit pricey to me.
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Old 04-04-2019, 07:37 AM
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Re: 89 350 TPI Replacement/ Crate engine options

Originally Posted by GTA1990 View Post
Not sure what the lift of that cam is but if you’re trying to squeeze what you can without machine work, also get the appropriate keepers/locks. I saw a c0.03 increase with some comp keepers over stock l31 ones

some have also got extra lift from different valve seals
The lift of that cam was designed to work with STOCK L31 heads when run with a 1.5 rocker ratio.
The lift is 0.473" on both intake and exhaust.
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Old 04-06-2019, 08:45 AM
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Re: 89 350 TPI Replacement/ Crate engine options

The T-5 will take it as long as you don't dump the clutch.

Originally Posted by mxnoah418 View Post
Well I definitely dont want to up the hp to more than the t5 can take. We just swapped the auto out for that.
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Old 04-06-2019, 02:23 PM
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Re: 89 350 TPI Replacement/ Crate engine options

Very interesting, all.

Last edited by mikeceli; 04-06-2019 at 02:32 PM.
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Old 04-07-2019, 03:29 AM
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Re: 89 350 TPI Replacement/ Crate engine options

I was reading about the L31R in Summit/Jeggs, for my '89 IROC Z Vert. Currently a LB9 305 TPI/ AT. . I'm thinking it's cam has too much lift and duration, to pass Ca. SMOG . Anyone?
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