GRAND PRIX 1992 LO5 TBI from roadmaster to 3.8L 84 GP

[ck80]

I am, a lot of threads to read through. This guys telling me $750 for motor, $1000 with Trans. I don’t want to change the Trans right now as I won’t have time to shorten drive shaft and such but feel it’s worth it.
Thinking just bolt the stock motor in for now. Then when time isn’t a factor I can switch build up the motor, switch Trans, gears and everything else with it.

I'd think your car has a th200 metric.... and a short tail th350 is identical in length to a th200.

You don't need to touch the driveshaft.

For a quick swap, nothing is quicker than switching engine and trans as a unit if you have the space.... no need to mess with bellhousing bolts, flywheel, gapping the starter, etc etc etc.

 

[Rehab]

Yes I have the Buick motor but kinda seems to be a waste. This particular one is 160hp and 260 torque. My roadmaster engine is 180hpand 300 torque. Then the cost and lack of avalabilty for parts with the Buick is crazy. The SBC is obviously available with plenty of options.
I can get a Cam, Intake, carb, headers and full exhaust kit for $1200 where as I'm paying $1000 just for the SBB and then all parts are costly.

 

[olds307 and 403]

The Buick more expensive to build. There are advantages, it is a very light motor, like 400 pounds. Add dual exhaust and you will have equal performance to the sbc 350. All the 350's those years had similar hp and tq numbers. Remember low compression, tiny came and very restrictive pellet converter, single exhaust was the reason. A T/A aluminum intake down the road and a mild cam will go a long way. I took a 76 Olds 350, rated at the same power, added a Performer intake and cam, shorty headers and crappy dual exhaust and ran a 9.9 in The 1/8(mid 15's 1/4) with the ignition breaking up top. That is with a 1900 flash stall, 2004R and 3.42 open gears with slicks. Your 3.8 would be at least 2 seconds slower in the 1/4, probably more like 3 or 4 secs, which is a lot. The Buick 350 is a direct swap, the Roadmaster swirl port sbc 350 is not. You will need G body sbc frame mounts and will need to remove the Buick ones, a PIA. Make sure the serpentine set up will fit in your Regal as well, since no accessories will swap between Buick and Chevy. Good luck.

 

[olds307 and 403]

Take a look at your current trans, if it has Metric on the pan, it is a TH200C. Also no vacuum modulator is another tell sign, needs a line added for a TH250/350. If the Buick has the short tail 350, make sure on length and is a TH350, it will also be a direct swap. As you know the 700R4 in the Roadmaster needs the driveshaft shortened. A TH200C is on borrowed time and may fail almost immediately if pushed hard.

 

[olds307 and 403]

That sbc LO5 is probably over rated for power as well. Tiny cam, horrible heads and maybe 8.5 to 1 compression, not 9.3 to 1. I take it you have a carbed sbc intake on hand, you will need one.

 

[Ribbedroof]

I can get a Cam, Intake, carb, headers and full exhaust kit for $1200 where as I'm paying $1000 just for the SBB and then all parts are costly.

I'm a jerk

That's a waste of $1200 on a 305 that has limited potential (never going to be able to put heads with decent valve sizing on it) as pointed out elsewhere.

And I SERIOUSLY doubt you're going to do a cam and top end swap , as well as changing from Buick V6 to Chevrolet V8 in 2 days, let alone have it running and driving safely in those same 2 days

I'm not a Buick guy, but it's a way easier swap for about the same end result...a G body with a low power emissions-era V8 swap.

I'm also inclined to think that by removing the injection and it's management system, you're going to lose some of that stated HP/torque when it goes carb'd....possibly to a pont where it produces less than the Buick.