60 days in on my 90 day rebuild. Goin to try a motor upgrade next. Any advice on going from a 350 to a 454?

[bucket]

Just trying to give a guy the heads up that it's not as easy as people will say. I live in Az so cooling is a deal breaker. I put a pro-cam fuel pump that came with its own issues, SB fan shroud won't cool a big block due to how deep the fan is in the SB Shroud...etc, etc...
These are just some of my experiences swapping in a big block where a small block was...

Like I said, there are variables. It literally can be as easy as people say. Just because there can be variables doesn't mean those people are incorrect. Like anything else, experiences can vary.

I'm on the other end of the spectrum as you. I bolted the engine right into my '84. My engine came with an aftermarket pump that fit and worked just fine. I don't tow with the truck, so the radiator does a fine job keeping the truck cool in city traffic in 100* weather. I didn't have a shroud to deal with because I had already installed dual electric fans from another GM vehicle. Other than changing the exhaust to mate up with the big block headers, it was exactly the same as swapping in another small block.

 

[peats]

I already know that I'm like a broken record, but I would put in a 400 and truly simplify the swap. Big block torque and small block budget.

 

[Shoote]

It is an easy swap with the exception of a "few" pain points. Most have already been mentioned. I have done a 305 to 502 and a 350 to 454. The areas I had issues with are:
Fan shroud
Radiator must be bigger for 454
Radiator hoses
Headers
Ac system
Motor mounts for big block
TV cable bracket on carb
Torque converter if an automatic transmission
I did the 454 swap last year and used coated headers that are Summit brand. Fit well on my V10.
I am sure I am forgetting a few things but that is a good list to start. I have no regrets. Love the big block with 3" true dual exhaust.

 

[streetrod don]

Best adviceON’T!..I have 3 square bodies. 2-5.3 LS (this is a very practical swap. And a blazer with an LT4. It will blow a hole in the wind. Currently building a C10 with a modified LT4 and 10 speed. For a budget build a 383 is hard to beat. I have a 59 with a big block. Gets about 6 mpg. Don’t like anything about it.

 

[Turbo4whl]

I still have a mechanical fan and it keeps it cool well, so not sure what shroud was used

Fan, shroud and radiator are different.

The shroud from a 292 I6 will hold the original SB radiator in place just fine. Add a small metal bracket to one end mounting bolt. The SB radiator will also cool the engine fine as long as you use the nice 7 blade thermal fan from the BB.

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I already know that I'm like a broken record, but I would put in a 400 and truly simplify the swap. Big block torque and small block budget.

This is so true ^^^! If you build a torque BB the 700R4 or TH350C will have trouble in stock form. Many ways to upgrade these transmissions, but if you use the TH400, you are one and done.

As for the few that say keep the small block, I disagree. Gotta love the Rat!

 

[Ricko1966]

Any factory big block head will out flow any factory small block head. Big blocks also already have long rods.If you aren't getting 10 mpg or better it's how you built it,not because it's a big block.

 

[GTX63]

It is all preference. I don't know that a 454 is always an upgrade over a small block unless your primary purpose is power or visual appeal.

 

[bucket]

Any factory big block head will out flow any factory small block head. Big blocks also already have long rods.If you aren't getting 10 mpg or better it's how you built it,not because it's a big block.

Or it's poorly tuned.

 

[Catbox]

Any factory big block head will out flow any factory small block head. Big blocks also already have long rods.If you aren't getting 10 mpg or better it's how you built it,not because it's a big block.

My foot turns out to be the biggest issue with the big block and mileage above 10mpg.
I did commute into the city with it for 2 weeks getting an average of 12mpg though.

 

[jjodan234]

Thank y'all so much for the input and advice. After talking with some local old school race track from the 80s guys im going to go with rebuilding the 350 and rebuilding the rear end. It will take me all winter, but didn't plan on driving it in the snow and mad chloride roads of Colorado anyway. I will keep updating post and photos.
Also to add, the color is " Nardo Grey" its an Audi color

 

[legopnuematic]

@Turbo4whl a fellow dual snorkel-er!

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[jjodan234]

Got the windows tinted today. Just a few more weeks of enjoying the summer drives and then ill start the motor rebuild

 

[JBswth]

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What transmission do you have? If automatic, you need a turbo 400 with a 454. You will soon destroy a turbo 350.

J. B.

 

[bucket]

What transmission do you have? If automatic, you need a turbo 400 with a 454. You will soon destroy a turbo 350.

J. B.

Eh. Depends on the application and use. And also the health of said TH350.

 

[idahovette]

^^^^^^^^^^^^THIS^^^^^^^^^