old chevy inline six question

[Dan Barlow]

I am thinking on switching over my daughter's old truck (68 ) Chevy from a 250 six cylinder to a 350 Chevy. Do these engines share the same flywheel?

[squirrel]

Yes. The swap is kind of a bolt in...but not exactly. The V8 trucks had the engine moved forward, so they had different frame brackets for the mounts, and the bellhousing crossmember was different and in a different place. You can put the 8 where the six was, it just won't be quite stock looking, and it's kind of tight at the firewall....I don't know how well it fits back there.

The bellhousing and flywheel end of the swap is all the same, that's the easy part.

[Dan Barlow]

So just to make sure, it won't be out of balance?

[68scott385]

My '67 was originally a 6cyl that a PO had put a 350 in on the 6cyl mounts. As Jim said, it is snug against the firewall but it does fit, even with an HEI distributor. The only interference problem I ran into was trying to use tall valve covers, the right one hit the firewall, but short valve covers cleared fine. IDK if I have any pics that show enough to help you decide whether to get v8 brackets or use the 6cyl mounts. I have a set of gently used motor mounts for that application if you're interested.

[Barry Donovan]

I did that to my chevelle as well..250 to 350. nothing seemed tight anywhere, but I was not paying attention much to the less than four hour swap and driving home. Just simply got it done. there is a header anomaly, but what else is new.

[squirrel]

So just to make sure, it won't be out of balance?

no balance issues. All the chevy sixes are neutral balance, and all the 350s that will accept that flywheel are also neutral balance. (uh....if the 350 is 87 or newer with the one piece rear main seal, then you do need to get a different flywheel)

The clutch might be kind small for a 350, although trucks sometimes had big clutches on the six.

[Dan Barlow]

With all you said there Jim, I was golden.Till you brought up that one piece rear seal . I was going to put the '87 GTA's original 350 in there . And while I do have a 74 350. I had it built to about 300 horses and I was planing on sticking it in a S10 ( like where its be before , a couple of times ) I'm not sure I'm willing to give it up . This will take some thinking.

Scott, thanks for the info and the offer on the mounts. Not sure yet. Thanks both on the clearance issue at the fire wall. I was told it had to be moved by the brother in law that is usually thee authority on these things. If I'm going to end up with it eventually I think I would like the motor shoved back . Since I would eventually slam it and try to make it handle well. I does have that truck arm suspension too. Any way thanks again.
Barry, Thanks for kicking in also.

[Scott Liggett]

Only sbc 400's and 454's are externally balanced. I think you can get V8 frame mounts from LMC Trucks.

[squirrel]

Only sbc 400's and 454's are externally balanced. I think you can get V8 frame mounts from LMC Trucks.

....and 87 and newer 4.3, 305 and 350 chevys. There isn't room on the crank flange for the weight with the one piece seal design, so the flywheel has a weight. It's the same for all 3 of these engines.

[rightpedal]

Hey Dan
I used a 99 3/4 ton truck flywheel when I swapped the vortec 350 into the 66. I am pretty sure I used a clutch kit specked for the 66. The flywheel was about a $100 at advanced auto and was in stock so we just mocked up everything in the store. I will look around and get the numbers for you.

Steve

[Dan Barlow]

I'm really looking hard at selling it and a old 4x4 4dr Jimmy that needs a head due to a broken off spark plug . As in nothing but the threaded tube part left to shoot air and gas mixture out with a loud pop. To be honest, I don't want to fix either one of these in my cramped cold garage. I can scrap them both out and get a running 4.3 s10 to get her by till she gets her bonuses from work for moving with them in a month or two. Then when she is done with it I can small block it. When its warmer.

[oj]

Those old 6 cyl can be tough and fun, heres' one i just finished in a '52 5 window.

[DanStokes]

I have TONS of spiffy 250 parts - many of the go-faster variety. And 3 engines including the flamer from the race car (really not significantly hurt). I mean, WHY would you take out a groovy six and put in a SBellybuttonC??!! Give a shout! Also have an infrared heater and 2 propane bottles I can lend you. Worth a trip to NC, I think! We'll be happy to put you up.

Dan

[DanStokes]

Those old 6 cyl can be tough and fun, heres' one i just finished in a '52 5 window.

That's the early style "Stovebolt" engine, not the 250/292 style. Pretty motor, though.

Dan

[Loren]

Those old 6 cyl can be tough and fun, heres' one i just finished in a '52 5 window.

That is nice...love the detail and plumbing.