Hey guys, first thanks for all the past help with my car... I have an 84 Z28 HO and plan on changing to a 350 that came from a 85 truck, First is there anything I should know that would make the install easier. And performance wise what could I do to increase performance and gas mileage. Again thank for all the help and any and all info is appreciated.

 

Cam, Springs, Roller Rockers, Intake, Distributer,Wires,Carb all the basic parts, should give u a good all around motor. If u want to go in deeper you can get a set of heads.

 

Put the 305 heads, intake and carb on the 350, add headers and exhaust, change the cam.

 

You'll need to use a knock sensor for a 350 TPI to make the CC Carb and distributor work properly, but thats not a big deal.

 

And there's no way to increase performance and mileage at the same time - they are mutually exclusive - more hp = less mileage, period. It's a trade off, and you have to decide where on the scale you want to be.

 

No its not. Improve engine efficiency and you can increase both power and economy.

(higher compression ratio, modern cylinder heads, better cam, less restrictive intake/exhaust systems, more powerful ignition system, among other things)

 

There are hundreds of ways to improve power and efficiency. Compare the mpg of a 5.7 tpi to a ls2...

 

Or compare your efficiency and power when you set your timing to 8 degrees ATDC with no advance.

 

Thanks for the info, I was thinking of going with the 305 heads and a mild cam, msd ignition, to start. Would I need to swap out the pistons and what intake would y'all recommend the 350 is carbureted now

 

The L69 intake is fine, or you could upgrade a bit to a Performer RPM or similiar.

 

To swap out the pistons you'll be doing a bottom end rebuild - this can get expensive in a hurry. If its not necessary, don't do it. The pistons in the 350 now are fine if they are not visibly damaged and the rings still seal.

For an intake... the aluminum L69 (5.0 HO) intake is actually pretty decent. It will support about 300hp+ pretty easily, so I would just clean it and reuse it.

MSD ignition - at this point, it won't benefit you do use it. I'm gonna get some flack for this, but the only REAL benefit of an MSD ignition is the multiple sparks at idle, which really only helps idle quality a little bit when you have a GIANT cam that idles really poorly and smells really bad. I've had a full MSD ignition in my '83 for about 3 years and it didn't really improve anything but cleaned up the idle a little bit. Its a good system, but it just won't benefit you at this point. Just put a good quality high-powered ignition coil in your existing distributor, as well as a new cap and rotor, and plug wires, and you'll be set.

As for the cam... one thing I tried once that actually worked out really nicely, was using the L69 cam in a 350 similar to yours. Its actually the same cam the Corvette used in its 350 before they used the L98 engines in them. If its still in good shape, put the cam from the L69 into the 350 with a set of new lifters and a new timing chain/gears set. Its a pretty nice cam IMO. You'll have to do the cam break-in process just to break in the new lifters, but thats not a big deal.

 

Multiple sparks at idle is just an attempt to keep short-duration CD sparks in the chamber through as much crank rotation as the long-duration LD sparks of a stock ignition.

 

Multiple sparks at idle is just an attempt to keep short-duration CD sparks in the chamber through as much crank rotation as the long-duration LD spark of a stock ignition.

 

I agree for a mild small block like yours, a high output coil, msd wires, and new distributor would be fine.

 

If the stock distributor's bearings arent totally worn out, theres no reason to replace it. Just the cap, rotor, coil and wires. Maybe ign module too if you really wanna make it like new.

 

Shim the endplay while you're at it.

 

Thanks again for all the info guys, going to pick up the 350 today and get everything going.. I will update my progress when I can

 

do u still need the o2's for it to run?

 

It will still start and run, if thats what you're asking, as the ECM will ignore the O2 sensors while its in warm up mode (they don't function untill a certain temperature) but once it gets past that, it will go into 'limp-home' mode if its not getting any signal from the O2 sensor. It will run, but poorly and make no power.

 

For the record, there's only one O2 sensor.