Will my 454 fit in my 1978 Stepside without much hassle ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**57NAPCO** · 03-12-2025, 07:49 AM

Thinking about doing something (fun?) with my 4X4 Stepside that I bought 3 years ago , it’s just been sitting…

I’m sure it will fit just wondering what I’m up against ? The truck has a SM465 and a 350 in it now. Actually there is nothing wrong with the 350 other that I’d just like to use the big block (that was in my 84 K30) that’s been sitting in the shop.
Thoughts, tips, positive or negative
…..On a side note, what are my options, if any, for something other than the sm465 ?

The customer…

**Getter-Done** · 03-12-2025, 07:58 AM

I had a 454 in a 76 Blazer.
It fit no problem.

The only thing that would not work is the fuel pump that was on it had the Huge bottom canister on it.
This was a fuel pump for a Car.
There is no room for it because of the crossmember.

A regular short fuel pump will work no problems.

**kwmech** · 03-12-2025, 01:26 PM

It will literally bolt right in. I did a 502 conversion for a customer a couple of years back. Went with a TH400 though, that was a bit more work

**57NAPCO** · 03-12-2025, 04:42 PM

Thank you both very much

03-12-2025, 07:49 AM	#1
57NAPCO F’B’D guy Join Date: Feb 2004 Location: Texas/Maine Posts: 2,281	Will my 454 fit in my 1978 Stepside without much hassle ? Thinking about doing something (fun?) with my 4X4 Stepside that I bought 3 years ago , it’s just been sitting… I’m sure it will fit just wondering what I’m up against ? The truck has a SM465 and a 350 in it now. Actually there is nothing wrong with the 350 other that I’d just like to use the big block (that was in my 84 K30) that’s been sitting in the shop. Thoughts, tips, positive or negative …..On a side note, what are my options, if any, for something other than the sm465 ? The customer…

03-12-2025, 07:58 AM	#2
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 9,870	Re: Will my 454 fit in my 1978 Stepside without much hassle ? I had a 454 in a 76 Blazer. It fit no problem. The only thing that would not work is the fuel pump that was on it had the Huge bottom canister on it. This was a fuel pump for a Car. There is no room for it because of the crossmember. A regular short fuel pump will work no problems. __________________ ________________________________________________________________________________________ ____________________________________________ The early bird gets the worm, But the second mouse gets the cheese 85 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

03-12-2025, 01:26 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,941	Re: Will my 454 fit in my 1978 Stepside without much hassle ? It will literally bolt right in. I did a 502 conversion for a customer a couple of years back. Went with a TH400 though, that was a bit more work Attached Images

03-12-2025, 04:42 PM	#4
57NAPCO F’B’D guy Join Date: Feb 2004 Location: Texas/Maine Posts: 2,281	Re: Will my 454 fit in my 1978 Stepside without much hassle ? Thank you both very much



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