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Treozen 03-04-2008 11:01 PM

replacing a 454 with a 350......
Hello folks....thanks in advance for any assistance!

Here is the story - I'm looking to buy an older pickup for general hauling (home depot, yards stuff, lumber, etc) and I've found one thats reasonable but its a 454. Now a 350 small block is a good friend of mine and we go way back, but this is my first meeting with Mr 454.

The truck is a 76 GMC and has 150k miles on its original all stock 454. I drove it and it seemed to drive out OK - no nasty smoke or warning sounds. Had a little white smoke but it was cold out so I'm not suspecting a head gasket, but I digress....

To cut right to it.....the 454 seems "ok" but it certainly looks like its from 1976 and I really have no feel for how well, or not, it was treated. If I buy this truck and the 454 dies - I'm probably going to take out the 454 and drop in a 350 (I wont need any more than that for my purposes anyway). My question is - does anyone have a good idea as to what issues I might face making that swap? Tranny? mounts? wiring?...etc.

I hope the 454 keeps ticking along, but I'm trying to plan ahead.

Thanks again!

Stroke 03-04-2008 11:25 PM

For a minute there I thought you had seen the light. The only problem you'll have is from those you tell that you swapped out a pig block for a small block.

DR132 03-04-2008 11:35 PM

everything should line up perfectly...nice thing about chevy's, particularly the trucks, everything is interchangeable!

Treozen 03-04-2008 11:59 PM

Great news on the 454 - 350

Originally Posted by DR132
everything should line up perfectly...nice thing about chevy's, particularly the trucks, everything is interchangeable!

Thats gret news....

Does anyone have any thoughts on a 454's reliability? Is 150K a big deal for that engine? - I suppose it depends on care and how it was maintained.

Double_v23 03-05-2008 06:12 AM

Depends on what you are doing and what you are willing to do to the engine.

If you are not looking for alot of torque then the 350 is the way to go, if you want some low RPM stump pulling power then go with the 454.

You will need to do a few things to make the 454 more efficient, but in the end you will have a solid, reliable, powerful engine that you will be happy with.

11echo 03-05-2008 08:13 AM

I had a 76 Chevy truck with a 454, it was a pretty good setup! There are a few "issues" that need to be looked at or watched. The one I got was a "fix-r-upper" ...guy said all it needed a new cam, well when I got it home I torn into it ...had to use vice grips to get the push rods out! (No wonder the cam was bad! *G*) SO I torn the whole engine down. ...both heads cracked in two places, running with lead free gas the exhaust valves were pounding out (sinking into the seat). BUT after dealing with those issues, new re-built heads with hardened seats, and a after the market flame hardened cam it ran great! That was 20 yr.s ago ...truck is gone now ...BUT not the engine! I still have it, re-built it again and waiting for my new truck project (64 1/2ton step-side). Big Chevy's are great engines! ...They do like gas, but the trade off are more power, and the same gas mileage whether you are hauling something or not. IMHO ...The only issue I think you'll have to deal with is brackets ...for the power steering, alternator, & A/C (if you have any) ...Good Luck!!

68NovaSS 03-05-2008 08:35 AM

I agree with all the guys above, I swapped a 454 for a 350 in a '74 Suburban, bolt-in deal. I had the complete 350 setup, brackets and all. Did it in -20 deg outside, got the burns on my arms from where I froze to the frame several times. :)

That Suburban was bought new and from day one there was a lifter noise. It went back to the dealer several times, they're conclusion - that's the way they are. I never tore the engine down, it ran fine until I pulled it for the guy. He was hard of hearing, never bothered him!

Treozen 03-05-2008 10:28 AM

Thanks for all the replies...sounds like I'll have no problems switching it out if I have to so long as I get the right brackets for the accessory equipment - I'd just as soon keep the 454 but not knowing its history, I'm just making sure I have a relatively easy option.

Ive been told 2 different things about the tranny and motor mounts - do the ones for the 454 line up and work for a 350? Seems from this thread that they do.

I should probably just go buy the thing and if the 454 gives up the ghost - I'll pull it, rebuild it, and pop in in something a littl emore fun :)

Double_v23 03-05-2008 01:28 PM

yes the motor and tranmission mounts are the same and located in the exact same position

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