I originally posted this on the engine Swap forum. They said that it was technically not an engine swap and that I should present it here - so here is my post.

I have a '91 Z28 with a 305 TPI and a 5 speed manual transmission. I want to convert it to a 350 TPI and a 6 speed. I will by a Crate Motor I suppose - so any suggestions on that issue are welcome as well. I have SLP Stn'ls St'l headers that I want to keep. In fact, I want to keep as much of my original intake and exhaust as I can. I will still use the car on the street but would like it to be fairly strong. Esp. along side those Mustangs. I know nothing about doing this so I need as musc detail as possible. A couple of my friends told me to come here and place a post - said this is where the wizards live.

Thanks - John

 

I also made a similar swap, except mine was the auto...making it much easier. Hawk I believe has a conversion kit of some sort.
Need bigger injectors, PROM for a 350 and also change the knock sensor to a 350..supposed to be different. If you can go aluminum on the heads it does help handling.

 

I just finished mine a little while ago. The only thing I changed was my knock sensor. The 305 injectors and chip aren't the best on a 350, but they do work. If you change the injectors, change the chip at the same time. That is the reason I still have the 305 stuff. they don't make chips for 350 w/5-speed, so you'll have to burn your own or get a custom one. I would suggest burning your own. That is what I plan to do as soon as possible. I don't know if the Aluminum heads really help in handling, but they do keep the heat down. They look cool too!
FBird

 

As a thought if you get an adjustable fuel regulator and turn up the pressure to what I don't know might be a solution. I have read some savy tuners put small injectors and turn up the pressure for better atomization. I have a 4 sp "auto" .. I am currently running a reverse full manual body. Weight out of the front end always helps.....a friend of mine who has driven the car who has several driving schools under his belt also said the car steered quicker...the car also has full hotchkiss suspension undrer it...goood luck.......

 

I used to have an 85 5.0 Tpi that I swapped to a 350. I had a shop do it, but I do believe the stock prom is ok with a 10-15% larger displacement change. Maybe that isn't the case with SD cars, obviously, mine was MAF controlled.

Also, they used the same heads, intake, TPI, manifolds ...everything, and it ran perfect.

Don't know if that means anything here, but I thought I'd throw that in there.

-Kevin

 

That's a very do-able swap. Although, the stock TPI intake will choke you down pretty good. I strongly suggest you learn to burn your own chips, I have found it to be very rewarding if not enlightening. The ZZ4 is a good call for a daily driver crate motor, but still, IMO you should consider another intake solution, there are an increasing number of options available. Check around here, there are quite a few running the ZZ4 and you will find most of them very helpful.