i have recently signed papers on an 81 vette, that is in absolute mint condition... matching numbers too! the only thing is that its the 190 HP motor for that year... kind of slow for a vette. my friend recommended a GM crate motor ... the ZZ4 355 HP 405 FTlbs of torque. for $2800!!

i want to know if this is a good idea.. i want to save the old motor because of the matching numbers deal... but i want to know if the transmission and the entire car can handle that much power. its a four speed manual tranny... nothing has been replaced since she was born... thanks all!!

 

Yep. Great decision.

I had my 4-speed '81 for about 2 months and then pulled the original engine in favor of a ZZ4 which I have since modified. Its a pretty straight forward swap. You'll need to swap the water pump and a few little things (search this section of the forum, there was just a post about what all needed to be changed on the ZZ4). You will however want to do some other items while you do the swap that will cost a little more now, but its better then waiting until you have trouble:
- resurface your flywheel for better cluch contact
- plan on a new clutch (I went with a CenterForce Dual Friction and I'm very happy
- get a new carb- the old quadrajet would work, but its pretty nice to take the computer out of the system
- new u-Joints on the drive shaft and half-shafts- A good maintaince item and a must if your going to run 400+ lbs of torque

Other items you might want to consider:
- switching to electric fans- I live in a hot climate but they work so much better and don't drag down your engine. Plus, since our '81s already had an extra, electric fan the wiring is all in place
- for ~$500 you can get the LT4 Hot Cam kit for the ZZ4. It'll bump the Hp up to around 400 and add another 15-20 lbs of torque. It includes a new custom roller cam, roller 1.6 rocker arms and new valve springs. Well worth the cost and much easier to install before you install the engine.
- a good set of headers (and I strongly recommend getting them ceramic coated). I have full headers but you might consider 'shorty' headers. I heavily modified my suspension which lowered my car and now I do have clearance issues
- new exhaust pipes out the back. Getting true duals under an '81 is tough but a good shop can do it. Don't order a pre-bent kit from Mid-America or anyone, just find a good shop. Consider a good X/H pipe too.

If you do it right you'll have a reliable car that really moves and yet drives super smooth. Plan ahead so that you don't have to go back and redo parts later and keep asking the forum for assistance. Feel free to go to my web site and go to my Vette's Resume (or go here: http://www.corvetteforum.net/c3/dshr...e-_show_v1.htm) Good luck, have fun and email me if you have any questions- I would be glad to help out however I can.

 

Welcome to the Forum!

Excellent decision. There are lots of ZZ4 owners here. As dshrack says, do a search of the archive and you'll find tons of info about the ZZ4 swap.

I'm still in the break-in phase with my ZZ4, but so far I'm VERY impressed. Post any Q.'s you might have.

 

what is the average break in time... how long till i could really push on it?

i am just signging the papers on the car today... so i really won't have the money till next summer... being 19 and all. but i want to find out all i can learn about this motor before i drop 3 grand into it

 

If you can get a zz4 for under 3500 I say go for it. I paid 3550 for mine and the motor cost dealerships 3500. The motor is great very responsive and good power. My first trip around the block I was going sideways. My old motor was descent, but the zz4 is on top. The warrenty was a big factor for me. As I do not want to replace a motor again until I am done with college.

Mark B. :cool: