I have a 66 cutlass i am restoring just for cruses and shows and sunday drives. I have been looking for a motor for a month or so now. 2 weeks ago i came across a 69 350 motor that came out of a 4 door cutlass. I got it on the engine stand and was tearing it down to do a simple rebuild when i came across a 1965 olds 425 from 65 jetstar.

My question is for just a stock rebuild which is the better motor to rebuild ? My guess would be the 425 but i read people having to put oil restrictors and do different machining into the big blocks, which i just cant afford right now. So would the 350 be better then ?

 

what do you mean by "better"?
the 425 will have more power, but get less mileage, the 350 will be the reverse. don't get me wrong, 350's are nice motors, i've owned some of the earlier ones. a 425 in a '66 cutlass will be a lot of fun, that's why i put one in my '67 cutlass. you don't need oil restrictors unless you're spinning the motor up and keeping the r's high. the machining is the same for either, unless there's an issue. pistons for the 425 may be a little more difficult to find/more expensive, but it's worth it imo. what tranny does your car have? that will be a determining factor too. a 2-spd. jetaway won't hold up to a 425 for very long(if you use the loud pedal much).


bill

 

i am running TH400 on either

 

sounds better, rides out better, slide tha *** end of my cutty out better. lol

i just didnt know if either motor was know to have issues. I really want to do the 425 and since you say there is no specil needs to just do stock rebuild it will be the one i build. i'll keep the 350 around for a spare....

From the research i found online it says that the 1965 jetstar has 370hp. The other info i found says its 10.25 compression and max hp comes in at 4800 rpm's. Does all that sound about right according to you guys ?

 

The 425 is a better engine in just about every meaningful way.

You can probably get by with a boreless rebuild, perhaps re-use the pistons even, then your new 0.040" head gaskets will provide a more reasonable compression ratio.

 

A stock rebuild on the big block without all that unnecessary stuff is still a stronger motor than the 350. The question you really need to ask yourself is, can you afford the ancillary equipment - larger radiator, different manifolds, etc?

 

well the 425 came with manifolds tranny pretty much everything from under the hood of the jetstar. I seen a set of the flowtech headers they say there for 400-455 anone know if they work for a cutlass chassis ?

 

Which unfortunately won't work in your Cutlass chassis. You need W/Z manifolds from a 69-72 442 or headers.

 

http://www.ebay.com/itm/Flowtech-Hea...374ac8&vxp=mtr


will these work on the cutlass chassis ?

 

The ad says that they do.

 

Couldn't the 425 be a 45 degree engine with the odd lifter size that will make the rebuild more expensive?

 

lol. Be nice Joe..
If you need a set of wz's, I have some
that will require a little work, $200.

 

^^ i think all 65 blocks are 45* but i am reusing the stock cam and lifters....

 

and everybody on egay is 100% honest

 

How many miles are on this engine that you'll be reusing those?

 

Make sure you found a 425 out of a low production 1965 Jetstar I. If not you found a 330 out of a bottom of the line Jetstar 88 series. The 2 speed Jetaway trans will be taxed behind a 425 BB.

 

Robski is curious too, alot of Jetstar 88's came with a 425 2-barrel 310hp. sure yours a high compression 425 four barrel IE:Jetstar1? Jetstar1's are base model Starfire's-what a nice ride!!! (65 only)

 

Actually zero Jetstar 88's came with a 425 and it was not an option.

 

wouldn't X/Y or 68-72 455 manifolds work too?


bill

 

ok finally got the block home and looked at. Motor has 63k miles on it says so on the title he showed me from the car...

it is a 386252 block' with "A" heads, and a 4bbl intake. and a 400 long tail shaft tranny on the back of it....

 

Ok so it seems you have an engine out of a 65 Jetstar I which would be a 370 HP rated Starfire 425,.... NICE

 

i feel like everything is coming together in my favor..... i am half temped just to see if it will start just how it sits.....

 

If its not too personal to ask, what did you pay for a complete set up like that? Nice find.

 

Yes, but W/Zs flow better. By the way, ALL 1969-72 A-body BBO manifolds are W/Z. Earlier ones (X/W for 65-67 and X/Y for 68) are not individual runner designs. Do not confuse the 65-67 W manifold (casting no. 389268) with the 69-72 W manifold (casting no. 402295). Also, the 65-67 W is RH, the 69-72 W is LH.

 

well he was asking $150 but i ended up trading him a set of stock sbc 882 heads and a crome alt. bracket and a set of pulleys.

 

Nice, so you basically got it for free.

 

pretty much. eberything i traded him i got for free : )