Chevy 350 OR Olds 403

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dougfather

Master Mechanic
Jul 11, 2006
286
5
16
Altoona PA
:?: I am planning to do a swap on my 84 Grand Prix that came with a 231 V6 (yawn). I want to wake up this car and get some decent performance out of it. I do NOT want a drag car, but something to go crusin in (so at least 200 HP) and not cost me a fortune in ga$ or part$. I had bought an Olds 403 from a friend that was out of a 78 Trans Am. In the mean time, someone has offered to sell me their 200-4R transmission (recently rebuilt) out of their 86 MCSS along with a 350 (bored 0.030" over) for $800. It comes with the Edelbrock Torker intake. I would have to buy it all. My understanding is that the 200-4R has dual bolt pattern and I need a transmission (200C won't cut it with any V8). As for emissions, I need to have it look like everything is there (I live in PA).

My question: Should I use the 350 Chevy or the 403 Olds? I am trying to keep somewhat of a budget and want some options for the future (maybe go fuel injected). Is any one harder to swap than the other from a Buick 231 V6? I know the Olds motors have great low end torque, but the aftermarket support has me a bit concerned. Chevy engines are plentiful, but what could I get out of a 350 in terms of power? I have an open mind about engines and am not a purist freak (so yes, if I had a Cutlass, a Chevy engine wouldn't bother me at all). What's my best bang for the $$$$
 
The 350/200r4 combo is a good one but the 200r4 wont take alot of hp without some mods. As far as hp from the 350. Skys the limit 300-350 is easily obtained for a very small budget. 350-450hp with a new set of heads and a nice bumpstick. then theres power adders! Turbo, superchargers, nitrous.
 
I'd ask who did the rebuild on the 200 R4. Like Red said with some upgrades they can take some horsepower but it takes a guy who knows how to rebuild a 200 R4 to do it...not just any transmission guy.... and I'g do with the 350.....cheaper and easy to get some power out of it.
 
There is no engine in the world with a cheaper cost per horsepower than the SBC. But I like to see Olds engines in Oldsmobiles.
 
I have a Pontiac. So either Chevy or Olds is ok with me. You all have talked me into going with the Chevy motor. So before long, I may have a 403 block enigne (in peices, but with all parts) up for sale.
 
Anyway, the deal is $600 plus my Olds 403 (in pieces and not running) for the engine and transmission combo. Anyway, I now must focus my research on Chevy Small blocks. Some questions:

1) Motor mounts on frame, does anyone have a picture of which holes to use?

2) What intake can I use? The engine is form the mid to late 70s. I *might* want to use an intake that supports the ECM. Not sure yet. As for pre-96 cars, Emsssion laws in PA simply state that emssion control devices are present (nothing about having to work).

3) Any good tech sites for SBC engines?

4) As for 200 4R, can I use my same crossmemeber that was with my 3.8V6 and 200C transmission?

5) Will a 200C torque converter work with a 200 4R?
 
dougfather said:
Anyway, the deal is $600 plus my Olds 403 (in pieces and not running) for the engine and transmission combo. Anyway, I now must focus my research on Chevy Small blocks. Some questions:

1) Motor mounts on frame, does anyone have a picture of which holes to use?

2) What intake can I use? The engine is form the mid to late 70s. I *might* want to use an intake that supports the ECM. Not sure yet. As for pre-96 cars, Emsssion laws in PA simply state that emssion control devices are present (nothing about having to work).

3) Any good tech sites for SBC engines?

4) As for 200 4R, can I use my same crossmemeber that was with my 3.8V6 and 200C transmission?

5) Will a 200C torque converter work with a 200 4R?

The motor mount holes are self explanitory. You'll know them when you get to it. ( IIRC, you will only use 3 of 4 bolt holes) You will , however have to pull the lower control arms to change them. But then, you need to pull them for the new springs anyways, as the V6 springs won't like a V8. While you're in there, put in new balljoints as the originals have likely seen better days ( they're press fit- so yuo may need a machine shop) and bushings. I would also find a car with the FE-3 or F-41 suspension and pull the front and rear swaybars. As far as intakes go, an Edelbrock Preformer EGR will take all the smog fittings, as will one offered by GM Performance, or even the stock aluminum 305 intake used by GM in the 80's. To use the ECM properly, I would just go ahead and pull the entire ECM wiring harness from a same year 305 powered Chevy or Pontiac G body, as well as the E4ME Q-Jet and Computer distributor and all attendant sensors, brackets , relays, hoses and such to make it work. I did all this when I initially did my 231->355 swap in my 1985 Cutlass using parts from a 1985 Grand Prix and a friend's 1984 G code Z-28. I even pulled the spark plug looms and the all important positive cable mount that goes to the block. Forget this, and you'll have a fire...like we did with the Z-28! Now to the crossmember...the 200C part won't even come close to fitting. You need one off a TH200-4R equipped G body, and if your car is older than 1985 ( or is it 84?) it will lack the proper frame bracket to mount the new X member. You'll have to fabricate one from steel stock and weld it in. That should get you started. There are quite a few other things you'll need ( PS pump and pressure hose, Alternator bracket, matched set of pulleys depending on what accessory drives you use, trans cooler lines, fan shroud, fan, hoses, belts, starter, radiator, etc), but if you just strip a complete SBC car you'll be far ahead of the game.Also, if you find a same year 305 G body, take the engine harness from it. It goes into the gang plug on the firewall and it is a 2- parter. The headlight harness snaps into it, and you won't need that section. The G body uses a common pin out on most vehicles for a given segment, so to swap engines, simply swap the attendant harness sections ( there are 4 possible under the hood: Lights, engine electrical and charging, Cruise Control, and computer.)

Oh, and one final thing: Check to see what gear ratio you have by checking the code under the sticker under the trunklid. If it is GU1 it's a 2.41:1 axle that will kill any performance you put into the car. If it's a GU5, 3.23:1 you're ahead of the game( found only in V6 3 spd cars and it was optional). Other possibilities are: 2.14 ( diesel-G72),2.29 ( some V8 3spd cars-GH2), 2.56( V8 OD cars-GM8), 2.73(GU2) and 3.08(GU4-optional lo po V8 ). Anything less than the 3.08 will kill your acceleration ( even the GU4 3.08 sucks!)
 
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