Is there enough clearance in front for the extra length of the torque converter?

 

it will help to take off the pulley from the HB. When I got my '88, I had to do this, because the engine was locked up.

 

Got the right side apart tonight. Man, it is an order of magnitude harder on that side with the brackets and extra stuff to move. Then one of the head bolts was reeeeaaaly stubborn. Glad it and/or my tools/knuckles didn’t break.

Not as much “steam cleaning”, and the valves are pretty uniform:




Engine is stripped down to a short block now - should be easy out.

I think I’m going to rebuild it for my ‘91. Now to choose a used engine for this car… How much should I pay?

 

Start surfing Craigslist and Facebook Marketplace. Don't get in too big of a hurry. Don't buy a 305. Actually a 96-99 Vortec 5.7 short block from a truck might swap in, and just use the aluminum heads from this engine. You can tell the difference between a 305 and a 350 by the front harmonic balancer. I saw an 85 TPI motor today for $250, and it was definitely a Corvette motor.

 

flood car ? never seen a motor like that.

 

After seeing the amount of rust on the cylinder walls, I would be inclined to purchase a known good L98. I'd refresh the new to you L98 with all new gaskets and a new water pump and belt and drop it in the car and go from there. The rust pitting may be too extensive even for reasonable cylinder boring. The cost you have in machine work alone may outweigh the cost of a used engine. Something to consider.

You may also want to consider posting a want to buy ad here on the forum regarding the engine. You may find someone here selling one for a reasonable price. Also Facebook marketplace is a good place to find used parts in your area. Would be nice to hear an engine run before buying it and if you find someone parting out a car locally, you may be able to hear the engine run before its pulled.

 

And the cam. The short block will bolt right in, but you probably don't want to use the truck cam...it's weeny..


How? In my experience, they look identical.

 

Here's a 5.7 Vortec in Phoenix for a reasonable price.
https://phoenix.craigslist.org/wvl/p...602980848.html
Or this one in Apache Junction might be just the ticket. You would be able to check it out really well. Get your heads refurbished and you would be good to go.
https://phoenix.craigslist.org/evl/p...607105936.html

 

Interesting. I didn’t know there was any compatibility with those newer Vortecs. For the second one that has been rebuilt, how would I know if I should use the cam that was put into it?

Also how much will I have to spend to refurb the heads?

 

The cam in that short block would be a great choice from what I know about the ZZ4. I'm not well versed in how it would play with the ECM on a 90 but I'm sure someone on here has used it and could give you some guidance. As for your heads, I would check with some of the engine builders in your area and get some quotes. A lot will depend on how much you want to put into a motor but I think this build will be less than the $2500 you are looking at for the used engines. That's if your heads don't have any cracks, or other defects that would make them unusable. If you take pictures as you have been of the build assembly that will be a good sales point when you put it on the market. The local head rebuilder that I use quoted me $250 plus parts to do a set of L98 heads. Not sure what local to you would be but shouldn't be too much more.

 

Sweeet - good data points. I also noticed someone selling L98 heads nearby for a few hundred bucks if it comes to that.

I texted the guy in Apache Junction and it’s still available - good find!!

 

I’m loving this new plan.

Going to pick up that rebuilt short block that @Blue Bucket List found yesterday. I don’t fully understand the upgrades the guy said he put in (the cam yes, but flat-top pistons look just like the ones on the outgoing engine. Were the Vortec stock ones different?). From what I’ve read the ZZ4 cam should be great without posing trouble for the stock eprom. If anyone has experience with this, thoughts please!

Another question for this engine: he says it has a one-piece rear seal. Does this have implications?

I brought the old heads to a local machine shop with a good reputation yesterday, and they will be cleaned and inspected in more detail. Initial assessment was that there was part eaten away from rust that would have to be re-welded, and then resurfacing would be necessary. Regular valve job was quoted at $250, but this will probably be all-in around $550 assuming no cracks or bigger issues.

Then I’ll need some parts, like rockers arms and pushrods (the old ones are just nasty), probably some new sensors (unknown), water pump, hoses, vacuum lines, and I’ll need to replace a number of harness connectors and repair frayed wires. Engine guy has lifters and a timing cover. I’ll reuse the old oil pan. Hopefully old alternator, A/C, etc. are good.

My ‘91 has roller rockers (was that way when I got it). Worth doing to this one?

All in sounds like I’ll be way under the $2500+ for a used engine, and get a brand new one. Can’t wait to fire it up!

This is my first time actually digging into an engine this deeply - had to buy a hoist and engine stand. Hope I don’t mess anything up!

Thanks for all the great suggestions! Corvetteforum at its best

I should have that old block out this weekend and will post pics of the bottom end.

 

The flat top pistons are indeed very much like the ones in your old engine. Higher compression ratio means more power. The truck engine that the Vortec is would have come with lower compression pistons so that it would be fine with regular gas. As for the lifters, I believe the ZZ4 cam was designed to use rollers so yes you will want to go with those. You could start looking at Summit and other performance parts suppliers to see if they have any good deals on a set with push rods and rockers. Even Rock Auto might be a good place to shop those. There is an almost limitless number of suppliers of parts for the SBC engine so shopping around is your friend.

 

^He's right; Vortec engine came with dished pistons.

Why not use the lifters, pushrods and rockers out of the rust bucket?

 

I believe the engine guy is giving me a new set of lifters, but will confirm later. As far as pushrods and rockers, I think you're right - I have been creating a parts list this morning and pricing stuff out, and it adds up quickly. Why spend money just for the sake of "new" if it isn't necessary? I was worried about the rust, but it's not on the contact points (e.g. tips of pushrods), so I should be able to clean it off and gently sand off whatever is on the middle section of the pushrods, right? The tips look nicely polished with no significant wear marks.

With that cam, which seems to have a little more lift than stock, do I need to worry about the stock rockers being ok with that? Or valve cover clearance like with roller rockers?

 

Yeah....I'd wire brush the rusty parts if the rust bothers you. It probably won't hurt to leave it either, but a quick wire brush'll make 'em look nice again.

Rockers won't care about the added lift from that cam, but you might need to change springs due to RPM and/or lift. Valve covers will be fine.

 

When you speak to your head rebuilders next you can inform them that you will be using a ZZ4 cam and they will be able to tell you if your springs will work with that amount of lift. This is a great thread and I'm sure a lot of us are rooting for you to have a successful build and get another C4 back on the road. Keep the updates coming along with the pics.

 

Totally!

 

Picked up that short block - I think it’s going to be a great solution. The guy runs a restoration shop and has a showroom full of engines and parts - he provided me with a full blueprint sheet showing all the specs. It was bored 0.030 over. With that bore, cam, and stock intakes he estimates around 300hp. Even if it’s not that fantastic I’m excited ​​​​​​​

 

I was hoping that this would be a legit build of the short block. Sounds like you got a good start and 300 HP is more than enough to get you in trouble if you are so inclined. I'll let the L98 experts on here guide you in how much you want to play with power adders but as the old saying goes" How much power do you want and how much money do you have?" I think for a street car that could be an everyday driver it will be fine. Only thing is you might like it so much you won't want to sell it. Wouldn't be the first time that happened.​​​​​​​