I have found a raging deal on a good running '91 305. My car is an 83 Z28 with its motor on the way out, burning clouds of oil upon startup, etc. The motor's owner says I only need to retain my carb and intake manifold to make this work. I wanted to run this by you guys before I buy it.

Thanks for helping a newbie!

 

Welcome aboard.

Yes, it's true. What version of a 305 is it? If TPI, that would be better than TBI. Your current heads are better than the TBI heads in terms of performance potential.

Clouds of smoke at start-up is valve stem seals. They can be replaced with the engine in the car. If the engine has other issues, then perhaps the change is worth it.

The '91 engine has heads with a different intake manifold bolt angle for the center two bolts on each side. This started in 1987. You can either get an aftermarket intake manifold with the proper bolt hole angles, or elongate those holes in your current manifold to get the bolts in.

Which engine does your car have in it now, the LG4 or L69? If you aren't sure, the LG4 has a single snorkel air cleaner and the 8th VIN character is "H". The L69 has a dual snorkel air cleaner and "G".

 

Thanks so much for the help. I have the LG4. The '91 engine I can purchase for $100, I have not seen it, so no word on TPI/TBI. My current engine failed emissions, and I'd just as soon get it out of there and deal with it as time permits. I was able to get the car for almost nothing then register it in my college town, which has no emissions test. Now I live in emissions land again so this is a concern, and makes the new engine appealing.

If you could point me in the direction of intake manifolds, that would be terrific. I have CNC/machine shop access, but I basically have to do the whole swap in a day and a half, so i think having a long block ready to roll is about my only option.

 

Edelbrock 3706. EGR, spread-bore, '87-up bolt pattern. It ain't cheap, but it will work. With exhaust and air cleaner upgrades, it should have more grunt than your LG4.

Emissions failures are more often due to what's attached to the engine than the engine itself, but at least you'd be getting a better engine (one can assume).

You'll also need a flexplate, if the engine doesn't come with one. '86-later are different than '85-earlier.