Engine swap

I have a 1984 Pontiac TA that has the 305 HO.  I am going to be upgrading the engine to a 350 or 383 stroker.  I auto cross the car in the STX bracket.  I am just wondering if anyone, and I know they have, have come across any significant problems with electrical and drive train.  I can not think of any reason to upgrade the current 305. Also the CPU will that need to be changed.

Thanks

Al  

Al, as far as installing and hooking up a 350 or 383 stroker in your TA goes, everything is a bolt-in procedure. Factory style exhaust is going to be a serious bottleneck to performance with either motor though. The best way to cure this is a set of headers that incorporates a cross-over pipe such as Edelbrocks TES and a good high flow converter and 3" catback single exhaust system ( there are probably a dozen to pick from and I believe Edelbrock has one as well).
As for the ECM (CPU), all it controls is the spark advance in the distributor and the fuel mixture of the electronic q-jet carb. Neither will give you satisfactory performance from the larger engine as they weren't designed with that in mind. My advice is to replace the distributor with either an earlier HEI or a performance HEI from MSD or one of the other manufacturers. That way you will have a performance timing curve and strong spark, plus a brand new ignition that won't let you down. I would then replace the intake and carb with something that matches your overall engine build goals. Considering your autocross plans, I would go with something like an Edelbrock Performer and a 600cfm carb for a mild engine or a Performer RPM and 750 carb for a more potent build. Simply leave the extra wiring unplugged and remove the bulb from the Check Engine light. You really only need the IGN power wire and TACH wire hooked to the non-computer HEI.
As for the rest of the driveline, the rear end is the weak link, being a 7.5" 10-bolt. They can be upgraded with better gears, c-clip eliminator kits and stronger axles and aftermarket posi units (Eaton limited slip, Powertraxx lockers etc.). You didn't mention the trans but the 700r4 auto, because of it's age and being an early design, will require some upgrades that any good trans shop can perform. The Borg Warner Super T10 4 speed manual was used in some early 3rd gen F-bodies and is a good unit, but the T5 5speed is more common and was never designed for more power, ask any 5L Mustang lover and they'll tell you how many transmissions they've seen destroyed by hopped up 5L motors. And they don't have the torque of a good 350 or 383! They can be upgraded to "World Class T5" specs but they are still a little weak for your application.
Steve  
A little help... 'cause we don't all have to learn the hard way!

That is great information.  It looks like that with the cost of a new tremec 5 speed and rebuilding the rearend that would be the major cost.  I can take it down to the muffler shop after the engines are installed and have an exhaust installed.  Looks like could easily be looking at another 6500.00 on the low end to do what I want. Momma will not like that.  I guess I will do it anyway.  

AL  

Be careful with the muffler shop, the 3rd gen cars don't really have room for a true dual exhaust. Although I've seen it done, the results were less than ideal, best to go with a large single system. Although the price may initially seem lower, the overall fit and performance of a properly designed kit will make the cost worth it. Momma will get over it, someday, maybe, maybe not! LOL!
Steve  
A little help... 'cause we don't all have to learn the hard way!

I am going to put a high flow cat on it.  Also any suggestions to improve the performance of the 305.  I might put a new cam in it.  I have been told by a friend who builds cars that he was in Van Nuys CA when the 1984 TA came off the assy line that my cam might need to be replaced with a stock cam.  I took him for a ride and he said the cam lobes were getting flat because it does not have the punch of the original production engine.

I was thinking of giving the electrical system little more punch also, new wires, MSD dist and so on.

Al  

Al, there are options for upgrading the 305 if you want to go that way. Start with a cylinder leakdown test or compression test to dtermine if the rings are doing their job and check the oil pressure with a real guage, don't trust the factory guage. A stock 305 calls for about 30-35psi max and as low as 5-10psi at idle, the higher the better.
Upgrades can include new cylinder heads (World Products S/R, GM Vortec are a couple that come to mind), Performer intake and 600cfm carb, ignition upgrades, camshaft/lifters/timing set and the exhaust upgrades we've already talked about. The important thing to remember when choosing heads is the combustion chamber size. With the dished pistons in your 305, you can't go much larger than the 58cc chambers in your stock heads if you want to maintain a decent compression ratio. Also don't go for 2.02"1.60" valves with a 305, it won't breathe that much and they will likely be shrouded by the small cylinder bores anyway. If you go with the GM Vortec heads, beware that you need an intake designed for the Vortec heads, GM and Edelbrock both make one.
For a 305 with only basic upgrades, I wouldn't go over 218 degrees of cam duration at .050" and .450" lift, in fact I've used the Edelbrock Performer cam and lifters for small blocks and had great results. The specs are 204/214 degrees@ .050" and .420"/.442" int/exh lift. Hope all this helps. By the way, what gears are in the rear and what trans do you have?
Steve  
A little help... 'cause we don't all have to learn the hard way!

I have the T-5 5 speed transmission.  I will have t check my pukin or vin number the gear ratio in the rear end.