bjayshock

Hey guys-

I am in the middle of changing the rear main seal on my 87 SC. It has a 305, CC 4-bbl, and a manual tranny.

I'm all the way to the flywheel, but I can't get the oil pan off to replace the gaskets. The manual calls for hoisting the engine from the top (I do not have an engine jack) or jacking it from the bottom and placing blocks of wood in the mounts. This seems very unsafe with the transmission out as there would be nothing holding the engine.

If I have to rent or buy a hoist, I am considering swapping in an engine from a 91RS. it's a 305, TBI, 700R4 setup. I need to prepare everything so I can make the swap as quickly as possible. Here is what I'm thinking, please correct me if I am wrong in these assumptions...

-Use the carb and intake manifold from the 87. Will it bolt to the L89 engine?

-Use the distributor from the 87

-Use exhaust manifolds from the 91. Are they the same dimensions?

-The sensors, O2, temp, etc. on the 91 engine should plug in to the harness in the 87.

-I cant think of any reason the flywheel and clutch wont bolt on in place of the 700r4 - am I wrong?

-Use the starter from the 87

I will need to have antifreeze, oil, and transmission fluid.

Is there anything I'm forgetting?

Thanks in advance for your replies and advice.

Bj

five7kid

iTrader: (14)

I wouldn't do it. You'd be taking a big step down in head quality. If the oil leak is the only problem, fix that.

The LG4 has more power potential, if that means anything to you. Restrictive exhaust and small cam are the main issues limiting the LG4. The '87 LG4 and '91 LO3 (it's an LO3, by the way) exhaust manifolds are not the same but are equally restrictive.

If you really think you want to do it, take everything off of the '87 and put it all on the '91 engine, including manifolds, distributor, sensors, senders, etc.

The only reason the '91 engine wouldn't work with the '87 manual transmission stuff is the '91, with an auto tranny, wouldn't have a pilot bearing in the crank. Since a new one should be part of any clutch job, just put one in.

bjayshock

five7kid-

Really? The L03 pulls so much harder. I guess the LG4 is just out of tune. Thank you- you saved me a bunch of work and wasted money. I assumed the roller cam in the L03 made it a better engine.

I'll just finish the job and keep the LG4.

Bj

five7kid

iTrader: (14)

'87 LG4 - 165 HP @ 4400 RPM, 245 lb-ft @ 2800 RPM.
'91 LO3 - 170 HP @ 4000 RPM, 255 lb-ft @ 2400 RPM.

Note the LO3 HP and torque both come at lower RPMs. Hence, the better seat-of-the-pants feel.

Either the LG4 or LO3 shortblock with cleaned-up LG4 heads, an upgrade cam, good air cleaner and good exhaust will make the LO3 feel lame.

BTW, '87 LG4 had a roller lifter cam. IIRC, it's the same cam the LO3 got.

bjayshock

BTW, '87 LG4 had a roller lifter cam. IIRC, it's the same cam the LO3 got.


I didn't know that...
Would a junkyard LT1 cam would be a good selection for the lg4? Will it work with the heads?


I guess this thread is a little off-topic now, but thank you for the information!

Bj