489 BBC Swap

[72Thunder]

Hey all, my friend has a Chevy 489 (bored and stroked 454) for sale and I couldn't pass up the opportunity to buy it. The motor will be swapped with my 350 and I have a few questions about the swap.

1. Would I need to do/buy anything else beside motor mounts?

2. I will mainly be driving my truck on the street and occasionally on the strip at local races. My rear end gear ratio is a 4.10 and I am wondering will higher "highway" revs hurt my bbc? I wouldn't think so, but I've had a few different opinions.

3. Will my TH350 be a reliable transmission? Will I need a shift kit or another torque converter?

Any and all help is greatly appreciated. Thanks in advance!

[68shortwide]

I'd think a new trans to handle the big increase in power which means a new driveshaft ... Just a thought. Probably a better radiator since you plan on driving it. Uh. Misc hoses and stuff like that.

[68shortwide]

Just noticed the occasional strip use. Def a new trans or you'll grenade the th350. Sell the 350/350 unit for a th400 and a driveshaft for a 396/th400 truck it should fit.

[72Thunder]

Awesome, thanks. I did get the rad (Griffin) and dual fan setup that was with the bbc aswell with my purchase. But good thinking for the trans. I did happen to notice that when I bought the truck, the original 2 piece drive shaft was upgraded to a newer one piece. Not sure if that helps or makes much of a difference in the long run.

[68shortwide]

What's the truck like, I love pics!

[72Thunder]

Bought her online from a fellow in Texas and have plans of giving her a makeover when the snow falls.

[72Thunder]

..

[72Thunder]

Here's the bored and stroked 454

[68shortwide]

Looks good, keep us all updated on the build.

[IIGW]

Originally Posted by 72Thunder

Chevy 489: !

you are going to need a list of whats inside that motor to answer most of your questions. Compression ration, head castings, cam etc..

Originally Posted by 72Thunder

1. Would I need to do/buy anything else beside motor mounts? !

motor mounts are the same

Originally Posted by 72Thunder

2. I will mainly be driving my truck on the street and occasionally on the strip at local races. My rear end gear ratio is a 4.10 and I am wondering will higher "highway" revs hurt my bbc? I wouldn't think so, but I've had a few different opinions. !

its your money, you can do whatever you want. My 4;11 rear does both my sbc and bbc just fine on the freeway, around 3800 at 70mph..

Originally Posted by 72Thunder

3. Will my TH350 be a reliable transmission? Will I need a shift kit or another torque converter? !

is your trans stock? If no, then pull it and rebuild it to be a reliable trans. But since you asked about your rear gearing, get a 700r4 and rebuild it to handle the bbc tq, then youll get an OD. Or a 4l60e, but then youll need a computer to make it shift.

Originally Posted by 72Thunder

Any and all help is greatly appreciated. Thanks in advance!

no worries, just think of it this way, it’s a grown up sbc. You have one in the truck running right now, so besides exhaust, there really is no difference. You can pull your 350 and install the 454 in a few hours and have it running. If it were me, id leave the trans the way it is now, to get the motor in and running and work out any possible non-foreseen problems. Then build a trans at a later date.

[68shortwide]

Motor mounts are a bit different. A few inches forward or backward I believe.

[68shortwide]

X2 on redneck

[1972RedNeck]

The BBC stands are different to allow for stranger insulators aren't they? The SBC mounts will bolt up but they get ate out pretty quick.

[bodydropped68]

I have a complete set of oe 1972 bbc motor mounts lmk if your interested i'm getting ready to list some stuff for sale.