small block to big block conversion

[red rumbler]

hey guys i popped my 383 and am looking at a 427 to drop in. ive been looking around and i think all i need is big block motor mounts right? ofcoarse exhaust will need to be changed but everything else should fit fine still right? im no longer running ac and the motor comes with every accecory needed. its a complete carb to pan motor.
any input would be great thanks guys

[INSIDIOUS '86]

your also going to need a big block radiator and if you have a th350 i would suggest running a th400 and if you have no swaybar your going to want one for that elephant thats going in

[rs72z]

Don't forget the bigger gas tank.

[john_p]

you'll need a larger credit card for the gas station!!! one thing that surprised me, around 20 plus or minus 2 , sbc, bbc.. i get 19 with my inline 6 and 3 on the tree.. i think it is one of those unwritten laws, square trucks are going to get around 20.. (or less)

congrats on the upgrade

[Your41Plague12]

If you're getting 20 with a square truck that's quite an accomplishment. Old trucks, at least every one I or people I know have owned, have gotten an average of 10, regardless of the drivetrain. You basically have it figured out. I would upgrade the radiator, but that's about it. You should be good to go.

[scottco]

I can buy alot of gas for the amount of a new pick up payment !!lol

[john_p]

no doubt, just between us, i was never a big rice fan.. they could get 50 mpg, i'll go with the detriot sound. nothing feels and sounds like a big block

[gofastbobby]

Originally Posted by rs72z

Don't forget the bigger gas tank.

this.

[red rumbler]

haha thanks guys and ya i already have a 4 core rad for the small block so i should be fine there and ya i was going to say my small block is around 7 to 10 km a litre ... but then again thats 373 gears turbo 350 high stall and a few goodies in the motor plus the occasional heavy foot spasum

[MadManAndrew]

Originally Posted by red rumbler

and ya i was going to say my small block is around 7 to 10 km a litre ... but then again thats 373 gears turbo 350 high stall and a few goodies in the motor plus the occasional heavy foot spasum

That's 16-23mpg. Very good milage...Lol. I get 10-13mpg in my 2002.

[andrewmp6]

You need to change out the front springs for something stiffer too.

[donut]

Originally Posted by andrewmp6

You need to change out the front springs for something stiffer too.

Not necessarily, IIRC the K-series used the same front springs for both, (many times the dealership didn't upgrade the springs for a snowplow and they're 500# heavier than a BB.) C series, dunno. Like INSIDIOUS '86 mentioned, I'd look into a front swaybar, then again, I'd recommend a front bar without the engine swap.

Do a site search, there are lots of folks that have done the swap. I did contemplate the swap with mine, but finances dictated selling the truck.

Dive in with both feet, whatever your missing will become apparent fairly quick.

[baclay9]

No need to change out the front springs. Its not that much heavier.

[red rumbler]

thanks for the mpg converstion lol not my strongest suit and ya ive already installed a front sway bar so that shouldnt be a issue either.

[yousesteers]

You do not need to change the front springs a big guy getting in the front seat will put more pressure on the springs than what the difference in the motors do I did not even change the springs for my cummins conversion