I'm thinking of pulling the original 350-300 motor and installing a zz4. Will it fit under the stock hood? What other fitment or other problems might I run into?
Thanks, Ron

 

I have been down that road Ron. I have my swap documented at

http://corvettec3.ca/zz4.htm

 

Thanks Binnie. Great write up and pictures. I'm also going with headers and new exhaust. With the drop base air cleaner it makes it under the stock hood? Your install looks great! How did you deal with the weight difference on the front end? I still have to see if I can swing the price, but I hope to do it by the end of spring if everything works out all right.
Ron

 

Yes, it will fit. Have a ZZ4 in my 75 vert. Am using a Holley Street Avenger 670 cfm carb with an Edelbrock 14' air cleaner with 3" high filter element and the wing nut makes just a slight dent in the hood insulation.
Anything else you need to know is contained in the exellent response by Binnie.
Many guys would suggest keeping the old engine for future originality purposes. My '75 has 1980 rear bumper and 1980 complete front end so originality for me is out the window anyway.
Good luck with the swap. Keep us posted on your progress.
Terry

 

This is how I fixed the weight difference:



I installed a monospring kit from VBP. I now have a height of 26.5" fender lip to ground. With the stock springs it was 29.5 with the ZZ4.

 

Thanks again for the replies Binnie and tnovot. With this help I'm sure I'll have less problems than I anticipated. I'm going to do a compression check on my stock engine first. I don't think it will come out too well, but I need to check it for my own satisfaction. It has no pep and just seems tired. If it doesn't check out, If it doesn't check out, I'll pull it sand install a new one.
Ron

 

Hello
I have few more questions to clear with ZZ4 installation.
I want to buy the turn key zz4 GM #12499712
I want to know what distributor w/Tach Drive I should order?
What FlexPlate I should order to connect it to 200R4 Bowtie trns'?
I will use a flex Fan, is it OK for the clearance from rad' shroud?
What alternator I should order to fit my wiring?
What alternator I have 1 wire or 3 wire and what the difference between them?
(72 vert with A/C PS PW PB)
Binnie77: from where you get the zz4 emblem and can you post a pic where you put it
Thanks
Avner

 

I bought the emblems on ebay a couple years ago. I will go through my files and see if I can find an email address for the supplier. They come with a double stick backing and they are placed on the sides of the hood where the L/82 or after market L-48 badges originally were.

 

The main things you will have to do are as follows:

Change to a short water pump. This will require changine the timing chain cover or just grounding down the bolts on the ZZ4.

If you have a manual trans you will need a flywheel for the one piece rear main seal crank in the ZZ4.

An adapter to place the temperature sensor in the head, unless you want to place it in the intake.

Those are the main changes you will need to make. There are some other items like a drop base air cleaner you may need, but it will all fit under the stock hood. You can reuse your distributor or use the HEI on the engine you just will have to change your tach or do without it. I personally went with an MSD tach drive dist so I could keep my original tach.

 

I switched to a Moroso drop base air cleaner and gained a little extra clearance. Their's is a bit flatter on top and the wing nut area is sunk down some. It got rid of the rubbing problem on my ZZ4 .