182plus44

Hey all,

I have had a 1990 with L98 and 700R4 that my dad gave me sitting around for years.

About 7 years back, I got it running well again, drove it for a few months, and the transmission went out. I was in high school at the time, so I had no money to get it rebuilt.

Anyway, I ended up getting the transmission rebuilt last summer, drove it around occassionally on the weekends for a few months, and parked it again.

This spring, I pulled it back out of the garage for some cleaning to get it ready for the year and decide what my next project would be to find that the head gasket had blown.

Over the last few weekends, I’ve pulled the engine, got the heads cleaned up with a full valve job, and decided to rebuild the whole thing.

I dropped off the block this weekend to get it tested, resurfaced, etc. and got a call today that the block was cracked.

So, I am pretty well invested in this car at this point. I know it would be cheaper and easier to sell it and buy a new one, but it’s got sentimental value to me, and a brand new transmission.

I’ve spent a good amount of time searching around the forum for what I can buy to rebuild on, but everything I have found relevant to me seems pretty dated and the engines don’t appear to be sold anymore.

I know that the most popular recommendation is buying a new ZZ4, but, at least from what I can gather, those aren’t manufactured anymore. However, please correct me if I am wrong and point me in the right direction

What recommendations do you all have for buying a new engine for this thing nowadays? This is my first real engine project, and I truthfully know just enough to get the engine out, pull it apart, and reorder stock replacement parts to reinstall.

I am not overly concerned at all about bumping up the HP from the original stock engine, but certainly don’t want the finished product to have any less power. My real goal is to save cost and go the easiest route possible with getting the car running again.

I’m looking to:
- Keep the existing transmission
- Keep the TPI system on top
- Keep the heads
- Keep the stock exhaust system (for now)
- Minimize fabrication

And, when it’s all said and done, hopefully not have to do any changes within the ECM (Mostly worried about cost on this one. Is this cheap enough to do that I shouldn’t be too worried about it in the grand scheme of things?)

Most importantly, I do want to do this thing right so that I can stop worrying about the engine for many years.

With all of that said, what are my options here?

LiveWire1

Check out engine rebuilders in your area, especially ones that rebuild marine engines. They usually have a selection of ready-to-go short and long-blocks, and boat engines can be built even better than car engines. Bring yours with you as the exchange and you'll be back in business right away.

Yinzcity

Are you looking for a new/rebuilt short block, or are you open to used? You may be able to find a tpi engine or short block that someone has pulled from another corvette for one reason or another. You'll want to look for something from 87 and newer since the rest of your components are for the later roller cam blocks and 1 piece rear seal.

84 4+3

L31 vortec block will be pretty close. Otherwise pretty much any 1 piece rear main seal gen 1 350 will drop right in and be fine. Nothing particularly special with them being a corvette application other than the piston volume iirc.

Cyclonite

Both Jegs and Summit offer crate engines from mild to wild. You can also check out Fraser engines and get a unit to swap. Many local garages may have other remanufacturing company sources too, like Jasper.

bjankuski

Any 350 SBC block from 1987 and newer will work just fine, should be many of them around. Just search craiglist or facebook and you should find one.

InfomanSS

In stock and ready to ship, but you might find a used block local and have a machine shop freshen it up with a 0.030 bore (this would mean new pistons that are 0.030 larger...easily available too).

https://www.summitracing.com/parts/n...make/chevrolet

funtoy

Hello from a novice myself. Reading your post it seems as if you have enough knowledge to "pull the motor and complete the heads" . Are you familiar with piston to ring clearance, torque specs on the main bearing and cam bearings and other assorted build information? If not, I would have two suggestions.for you. One would be to buy a standard 350 shortblock and have a builder build it to the factory specs or.... Two....Purchase a used L98 from a variety of Corvette scrapyards. I am currently in the middle of a similar project and was taking the same approach....That is low $ and keep the factory TPI. Unfortunately my cpu would not recognize my mild cam and head combo that I upgraded to. The car ran rich and never had the throttle response I expected. So Tomorrow I am replacing the TPI with a complete Holley Sniper Throttle Body system and Ignition. From what I've read great results. I have a post TPI to Sniper here on Corvette Forum and you can follow the thread after I post more tomorrow evening.

IN the meantime here is a link to a 1991 L98 TPI Complete motor for sale. 1991 Corvette L98 5.7 Liter Tuned Port Engine - Contemporary Corvette

I hope this helps...

89onlyZ51

I agree with what's been said before - any factory roller block will do, and they are a dime a dozen. You can go used, reman, or crate and be back in business. The one thing I will add, though, is that you MUST use your stock '90 L98 cam or something very close to it, or your car will run like poo when you put it back together unless you burn a new chip to match. Being a '90, you're speed density, and the ecu is particularly sensitive to cam changes, especially at idle and transitions off idle.

Mr. Peabody

YOU're very fortunate because you live in an area with a number of Corvette specialty shops. I would suggest that you get in touch with any of these shop to see if perhaps thyy have a short block they've taken out of someone else's car that you can use:

1) Brads Custom Auto (North Seattle)
2) Corvettes of Auburn
3) Wong's Performance Engineering (Vancouver WA)

Incorvettei

I would go to a salvage yard and pick up another engine out of a wrecked Vette. Around here you can find these engines easily and for not a lot of money
(15 minutes east of Philadelphia Pa)

cv67

He can do a tune for it also, used him a few times real happy
ZZ6 is the zz4 replacement btw.

dhirocz

Buying a vortec replacement and put your top end on it is probably the most direct route.

I would, however, consider a cam at this point. Doesn't have to be a big one at all, nor do you want a big one in a tuned port, but there's more than just power available with a cam swap. I used a c4 LT1 cam in a TPI, ran very good, improved mpg and throttle response too...tons of other options as well.

cv67

An increase of 10-12 deg duration seems to work real well on LTR engines.
Great manners and plenty of torque. Always wondered if using a more aggressive single pattern with a tigher lsa may be even better as you wont have a wide powerband anyways with the runner length so why not make it as good as possible. Just never tried it .

182plus44

Hey all, thanks for all of the great feedback.

I gave Brad's Custom Auto a call, which another member be had mentioned, thank you for that, and he suggested I go with this short block: https://www.summitracing.com/parts/nal-19419042

Originally, I intended to keep my crankshaft as well as my heads that I had rebuilt, but buying this short block seems like a better route as it will save me some time and potential mistakes with the pistons. I also like the idea of having the entire bottom end brand new while I am in here.

From what I have found, this looks to be as close to a factory replacement as I can get new. Does anyone have a differing opinions on this short block?


Also, a few folks mentioned the cam. I do plan to swap out the cam too. Mine may very well be fine, but while everything else is being replaced, it's another one of those might as wells.

The cam I am currently eyeing appears to be the closest to stock as possible, EngineTech ECK808: https://enginetechcatalog.com/Home/P...kittype=notkit

I want to keep it as close to stock as possible to prevent needing to do any further changes in the ECM/ I want it to run fine when I drop it in. Is this the cam for me? Is there a larger one anyone would recommend that would have no issues with the rest of the stock system? I saw one user mention they ran into issues when upgrading theirs.


Thanks again for everyone's feedback.

IWR

I'm basically in the same boat as 182plus44 (Trying to revive my dad's corvette which I drove in HS 20+ years ago...), and have been doing tons of research on a replacement for the old L98. My confusion is around the replacement short block that he linked in the post above, or even others out there like the L31 or ZZ6. In theory if I ordered one of these short blocks, would it be as simple as unbolting all the parts from the OG L98 and bolting them back on to one of these replacement crate engines? Like, a true bolt on / plug and play affair with no modifications necessary?

The ultimate goal would be a healthy, newish motor that can pass CA smog.

Thank you!

Duc96cr

California has more hot rod and custom shops than the rest of the world combined. They would be more informed as far as helping you get something that will fill your needs and meet smog laws. You should be able to get a crate motor from someone that will bolt in and meet all your requirements.

Phobos84

If it were me I would LS swap it

But if that's not the direction you want to go, then go to any self service (you pull it) style salvage yard. You can get a nice Vortech 4 bolt roller SBC for $300 or less and most yards will put a warranty on it. I would check clearances, replace cam bearings if need be and assemble with your aluminum heads and a nice cam upgrade. All in all it won't cost much and you would get a nice boost in performance. If you don't mind iron heads then keep the heads that come with the truck engine and enjoy the better flowing heads.

84 4+3

Listen, if you check them then you need to replace them. so don't check.

Phobos84

How could I have forgotten the golden rule. Looking at cam bearings is what makes them bad.