88Cutty GT

Need advice on what all I should do to put a Jeggs 350 Chevy crate engine in my 1988 oldsmobile cutlass 2 door.All imput is more than welcome thanks.

droptopron

There is a lot that goes into it. Your transmission may not bolt up. Chevy used a different pattern than Buick Olds & Pontiac but some transmissions facilitate both. You'll have to change frame mounts and motor mounts. Wiring will have to be modified. You will need headers or manifolds for the new engine. Most crate engines don't come with brackets so you will need to source all that.
Might I ask why you wouldn't consider an Olds 350 or 403? Find a core & have a local rebuilder go thru it. It may cost you more up front than the crate engine but you will be time & money ahead when you go to install it.,

88Cutty GT

88Cutty GT

I'm having transmission built up now,with both patterns .What exactly can I do about tha mounts? Can I go to junkyard,to get pieces and what will I be looking for? And far as the wiring modified can you explain.Could not find any olds engines here in Raleigh N.C.

DeltaPace77

While actually never did the swap myself, some 77' Olds 88's actually came from the factory with either Olds or Chevy 350's under the hood, so can't be to hard. My car currently has an Olds 455 under the hood, with Chevy 700R4 tranny in it. Bought an adapter plate, and shortened the drive shaft, to make it work. May want to check in the forums non Olds powered section, as bettin' someone could help you there.

mike machine

for me going to chevy from olds it is lots of works the wire no prob but all the front braket and pullies that you must find good luck.

Olds_71_442

Find a G Body Monte Carlo or Malibu that carried a 305. Even some Pontiac Grand Prix's carried the 305 Chevy. The motor mounts should fit the Cutlass. And if you can't find those, find a 79 - 81 Cutlass that came with the 267 Chevy. It should be quite easy to switch it over. I've gone from Olds to Chevy back to Olds and didn't have any problems.

joe_padavano

Welcome. It's unfortunate that you picked such an emotional topic for your first few posts. Many of us here frown on Chevy transplants in Oldsmobiles, and yes, I realize that the factory even did it. Unfortunately, while APPARENTLY less expensive, the Chevy motors are like navels (or another bodily orifice), as everybody has one. If you MUST do this swap, the Cutlass is the same as a Monte under the sheetmetal. Find a donor and get EVERYTHING you need.

As others have noted, an Olds 350 or 403 bolts in place of the anemic 307 and many here have done just that swap. A 455 drops in with only marginally more work, mainly in the need to slightly modify the accessory brackets to account for the taller deck height and to swap the exhaust manifolds. The 350/403 swap doesn't even need those items swapped - those motors are externally identical to the 307 and EVERYTHING bolts up.

OLD SKL 69

Welcome to CO! Joe said it best with the pros/cons of a SBC swap. Good luck with your engine decision.

rocketraider

If this is a documented GT conversion, it's a rare enough piece that if you don't keep the 307, you should at least use a 350-403 Olds engine for more power.

I can promise you Joe Johnston never spec'd a Chevy engine for those cars when they did the conversions. T&T wanted the 307-9 for them but by 1988 it was NLA except as a warranty replacement for an 83-87 Hurst/Olds or 442, and not emissions certified for 1988 model year.

Which number GT do you have? it'll be on a plate on the console, something like Cutlass GT No. XXX of 400- and production never reached 400. I'm also assuming you're somewhere in the Southeast though I've heard of a couple of GTs making their way as far north as Ohio and Pennsylvania. *EDIT just noticed you're in Raleigh

If you're determined to put a Chevy lump in it, I'd go thru GM parts department and get one of their crate SBC engines over a Jegs. The GMPD unit will at least have a warranty and some guarantee they put the right stuff back in it, which you can never count on with a jobber rebuild. And with all the aggravation this swap entails if you don't already have all the auxiliary stuff, you don't want to do the job more than once.