I know this has been gone over before, but are there any threads or member web sites that describe the instalation of a zz4 in a c3? I tried a forum search and got nothing.
Thanks

 

on the top tool bar go to 'other' then 'tech tips' then c3' then at the obttom is zz4 install..
or find it on corvettefaq.com

 

I will soon be putting a ZZ4 in my 1968. Keep in touch with what you're doing. In some ways it doesn't look like too big of a problem. A little re-wiring for the HEI will be required (and the alternator of the 1968 external regulator alternator if you have one). The temperature gauge is another minor problem, the ZZ4 won't accomodate th large diameter early C3 thermostat that screws into the cylinder head. You can put your ZZ4 temperature sensor in the thermostate housing (you'll need a new housing). If you have a short water pump (all the early SB C3's have the short pump), I think you'll have to grind down a bolt on the timing chain housing for the ZZ4 for it to fit the short water pump.

For me the biggest concern is that the ZZ4 has D shaped exhaust ports. I'd really like to get headers that match the exhaust port. Actually, I heard that the circular port headers won't impact engine performance, but its just a matter of principal that if my exhaust ports are D shapped, I'd llike to have the headers to match. The ZZ4 also has angle plugs in the head. I've bought a Headman Hedder for a standard SB straight plug head and it does fit my ZZ4 mounted on a Corvette frame. Even though the ZZ4 has slightly elevated exhaust ports (approximately 0.1 inches higher that the older engines) and angle plugs, the Hedman header for the standard SB slightly lower exhaust ports and straight plug heads does indeed fit the ZZ4 on a Corvette frame. I called Hedman and asked if they would make this header for me with D shaped exhaust ports and they said no. (!!!!) I plan to call around and inquire if a header manufacturer will make a custom header tht duplicates the Hedman. The Hedman header that I'm talking about is the only header that is specifically designed for the factory sidepipes of 1968 and 1969!

 

Well, I do not have much on the tips listed, but I will answer any questions you have. And if you want to see pictures of my install go here. http://bellsouthpwp.net/m/l/mlbcpa/zz4.html

 

I did the ZZ4 swap this summer without any major hurdles. The tech paper is quite good. I didn't encounter any problems beyond those described in the paper.

About the D-shaped headers - I called Chevy and talked to someone fairly knowledgable about this, and evidently Chevy has done its own testing on O-shaped vs. D-shaped headers on D-port cylinder heads and found no difference in flow. But I haven't seen the data so I couldn't tell you for sure.

Good luck and have fun! It's a great motor.

Dave

 

Guys thanks for the response. I'm going to look at the motor in a little while. Locale fellow has one with 10 hrs on it that he wants to sell.

 

Thanks to hear what you said about the D shapped ports. But I really wished that the header manufacturers would just immediately and with no hassle make D port headers. Hedmann said they would not modify their factory sidepipe header. This was for the factory sidepipe exhaust system(1969).