Olds 307 to Olds 425???

[CaliCuttie]

Hi gang, so there's an Olds 425 engine in my area, would this be a direct swap like the olds 350 & 403s are? I have a 200r4 transmission and 2.14 rearend gears in my '86 Cutlass Supreme. Thanks!! And if its legit is it worth the hefty price tag, taken into consideration possible engine build up, possible rebuild, etc etc. In other words, if its a tip top engine is 1200obo reasonable? I'm rather broke and can't really afford attempting to get an engine & heads rebuilt, built up, AND installed. If I can get an engine that's just done and drop and go that'd be ideal. THOUGHTS??
Thanks G-Body peeps!
-Mike
p.s: any stabs at fuel economy on a good day? good joke, right? i'm serious 😳

LINK to the Engine:
http://sfbay.craigslist.org/sby/pts/1726569677.html

 

[Blake442]

$1200 is kinda rich for my blood... It better purr like a kitten, and I better be able to hear it run before I bought it.

The 425 will drop right in on your 307 mounts, but I doubt your stock 200-4R will last long behind it.

 

[dogsht]

The 425 is potentially an outstanding engine choice imo but the 200-4R would have to be built to take it for very long. You could get a good shift kit such as the one http://www.ckperformance.com sells and give it a fighting chance to survive with common sense until you are ready to built it up. But regardless the 2.14 has to go and is not a match for the transmission. Its not a drop in because its a big block Olds and you have a small block Olds but much can be carried over and it would be a less involved swap than that of a different markey. check out http://www.robertpowersmotorsports.com for some good info. And http://www.oldspower.com. and http://www.cardomain.com/ride/1381227

 

[joe_padavano]

The 425 is ALMOST a bolt-in replacement for your 307. Externally, it is identical to a 455, which means that the accessory brackets from your 307 will require mods to work with the taller deck height of the big block Olds. The 307 motor mounts bolt directly to the 425. If you need new ones, get Anchor P/N 2328 or equivalent. The one difference to be aware of is the crankshaft bolt pattern. The 64-67 motors use a different bolt pattern than the 68-up motors, so you need the flexplate that goes with the 425.

As for your 200-4R, I still don't understand how a shift kit is going to fix the weak stator shaft and forward drum hub. You can get a hardened stator shaft and drum with a billet hub, but you need to disassemble the trans to install them. With these internal mods, the trans can live behind a big block. In stock form with a shift kit, not so much.

 

[dan2286]

$1200 could be a good deal depending what has been done to it. Try and see if he has receipts for everything he has done to it. Let us know what's in it and how many miles are on it, and we could determine if it is worth it. Also, for that kind of money, it would be very nice to be able to hear it run.

 

[dogsht]

The generic 200-4R with only a good shift kit would not survive behind abuse from a 425. It could only get him from a to b until he has time and or money to have a performance build.