Hi everyone-

I just joined the forum here and I have a lot of questions. On monday night my retired father bought a 1982 Trans-Am with the 305 4bbl and 3 speed. It's a project car for either restoration or modification. I've been doing a lot of reading and it seems that this car is not overly desirable or as unique as he hoped it would be, but the price was right. He was looking for a project car anyway. I'm helping him with the rebuild.

The car runs and drives okay. The 305 starts up and runs smoothly. However I am looking at options to wake it up a little bit. My original thought was to do a 350 or 383 swapout, but after thinking I might just pull the 305 and work with that. It's the original motor to the car from what I can tell and it runs okay, so it might not be the worst thing.

I have not done a car since I had my 1980 Z-28 that I sold in the mid 90's. I'm thinking of doing a lower end freshen up and going with a hydraulic cam, some kind of intake, a new carb, better ignition, and a set of headers. What would be the hot setup for a 305 with a stock bore and maybe a slightly higher compression ratio where I want something smooth, streetable, pump-gas friendly, and simple? This car will probably get driven a lot and go to local shows and it would be great with more power. I'm hoping to get somewhere in the 300 hp range, but don't know if it can be done easily with the 145 hp motor that came in this car. I want to stay naturally aspirated if I can.

Any input is appreciated!!!

Thanks

 

Welcome aboard thirdgen.org.

The first problem is the 305 has low compression due to dished pistons. To add to that, it has a tiny cam and tiny exhaust and tiny air cleaner snorkel. The good news is you can work with the heads and carb.

I would recommend finding a 350, at least a shortblock, and work with that. You could replace the pistons in the 305 with flat tops to raise the compression, along with new rings to insure good sealing, but rather than spend that money on the 305, spend it on a 350. A truck engine would be a fine core.

As mentioned, the exhaust is pretty poor. Nice headers like Hooker 2055HKR along with full aftermarket exhaust will make a big difference regardless of what you do with the engine.

From there, the options are pretty wide open. Here's a build that I think you would find meets your power hunger but is pump-gas friendly (without wanting too much of it):
- 350 shortblock core to rebuild. Bore it 0.030" over (standard clean-up over-bore), flat top pistons with 12cc total valve relief and dish.
- This head kit http://sdparts.com/details/scoggin-d...er/sd8060rakit . Includes everything you need to bolt them onto your shortblock except pushrods. These heads are about as good as you can get from the factory. The price can't be beat for what you get in that kit. If you decide not to go with Vortec heads, your 305 heads with 1.94"/1.60" valves and basic port clean up will be a good alternative. Consider pistons with a larger dish if you do use the 305 heads.
- Cam such as the Comp XE268. Not huge, but works well with the other factory stuff. If your 350 block has roller lifters, get the roller lifter version of the cam (XR264 or XR270).
- Dual-snorkel air cleaner (either find a factory "L69" air cleaner assembly, which are becoming harder to find, or something from Spectre or Ram Air Box). A "drop base" type air cleaner will be required to clear the factory hood.

Bolt your factory carb and distributor to that along with the suggested exhaust upgrades, and you'll have an easy 300 HP at the crank. Probably well over 350 HP, in fact.

A transmission upgrade to a TH700R-4 would allow much friendlier cruising. However, that is more expense and a little more work. But, it's a lot better than the stock TH200C.

 

Wow! Thanks for the detailed reply. That setup sounds very good. I had an experience once working on a friend's 78 or 79 Monte Carlo with the 305. It ran decent for what it was after we did the cam and intake, but it never made a lot of power.

I think the mild 350 route is probably the way to go.

It is nice to know that there are lots of upgrades you can make with headers, engines, exhaust, etc, without having to fabricate.

Personally, I was relieved when I found out this car had a Chevrolet engine in it. I didn't know if it would have some kind of Pontiac or Olds V-8 being that it was a Trans-Am and I didn't know much about these generation F bodies.

Thanks!