Big block swap?

[Chevyster3]

Hello,
 
     I have a beautiful black 1986 Silverado 2 WD short bed truck,  305/auto.  It was a gift from my older sister and my lady. I love it but the 305 gave out and transmission is tired too.  I want to restore it up to my real dream.  I am thinking about putting all new combo crate 502/auto. I saw a 1990/91 Silverado 454 SS that caught my eye about doing my truck the same way; so would you mind to guiding me to where I can go and get information on the parts that need to make it a big block/auto swap.. complete with axle? I think mine is 10 bolt 2.73, so where can I find 12 bolt 3.73 that would fit my 86 truck?  Thank you in advance and I look forward to hearing from you..
 
Morris

[VileZambonie]

Try the junkyard or a donor truck for all your swap odds and ends including the rear end you want. Look on Craigslist

[choptop]

I believe that in order to get a 12 bolt, you will need to look for a 78 or older. You may be able to find a 1/2 with the 454 already, so keep your eye open for that. Preferably a longbed, because they will be cheaper than a shortbed by a long way.

[joesgarage71]

I believe that in order to get a 12 bolt, you will need to look for a 78 or older. 

I had a 12 bolt in a 86 1/2 ton I owned. yup! It was factory said so on the RPO sticker
 With the 502 your planning on I go and get a 14 bolt. Theres alot of them around for a 100 bucks.

[choptop]

Arent all 14 bolts 8 lug???

[joesgarage71]

I think 88 and up where  six lug SF and 8 lug FF. He would be looking for a 5 lug wouldn't he. My bad

[Captkaos]

I wouldn't wast my time swapping from a 10 to a 12 bolt,  There is no gain one over the other.

A donor 454SS will give you the exact pieces for the swap as far as drivetrain as it was the only 14bolt with 5x5 pattern.

All motor mounts are the same for the SBC vs BBC, so just use those...