1977L48

so im getting alittle tired of the 350 in my vette, i have a 427 in my Monte Carlo, its a 74 454 block, with a 68 396/427 forged crank, 502 rods, L88 pistons, trick flow 280 heads, weiand intake, holley 750dbl pumper, rather large Comp hydraulic roller cam with roller rockers, around a 580 lift and 254 duration at 50. now im not running A/C or power steering on my vette, are there any surprises i should know about? i know ill need new motor mounts and headers, but besides that? i have a TKO 500 in the car. the 427 in the monte carlo, through a TH350, it made 405whp and 400tq, so it should be a nice improvement over the 350, just looking for any input. thanks

damoroso

No real surprises, you'll probably want more radiator and may want to go with electric fans for just a bit more space. Also, I found I had to run a AN8 fuel line to feed my BB, the 3/8's factory line was causing some fuel starvation issues for me. Depending on the intake your running you might have some hood clearance issues that would have to be addressed too. I didn't have to swap springs, and was even able to use the SB radiator hoses, just had to cut the lower a couple inches shorter at the pump end. I will tell you that your gonna really like have'n that BB in there though!!

illenema

One Nice thing about the c-3 you can put almost any size engine drops in.
Front springs, and BB radiator, hood clearance, also sometimes the brake booster clearance issues, BB power will be enjoyed!
Hope to god you have Power steering with a BB

John 65

Really not to many surprises. I put a 454 in my 77 also. It used the same motor mounts as the small block, and I left in the sb springs and have no issues or problems with them so far. Running a Performer RPM intake with a drop base air cleaner and a flat top, so the stock hood closes just fine with room to spare, which was great because I wanted to keep the stock look of the car.

To help keep the cost down, I didn't use any corvette big block acc brackets or pulleys. Went with a long WP and put the alt on the right side, not above the ps pump. Plenty of room to work. Put that $$$ into an aluminum radiator instead. The stock booster can probably be used but I used a new smaller one. Good luck with the swap. I had a lot of fun doing mine and I really love driving the car now.

1977L48

what about an oil pan, i have a re-pro of an LS6 oil pan i think

John 65

Don't know if that will work or not. Perhaps others can answer, but you need the room to clear for steering. Not sure if the big block corvette pan is the only choice.

Doug Kraft

Not sure about your oil pan but a Milodon big block stock replacement pan works just fine. You can use the same motor mounts, springs and rad hoses. If you don't have electric fans you will need a BB rad shroud. Also you will need the headers for your sidepipes but the tubes should work just fine. Just wondering if your doing the swap in Florida or in Mobile? PM me if you want some help.

1977L48

it would be done in mobile in my shop, alot of down time here has gotten me thinking about doing it

damoroso

I used the stock BB pan, but will be going with the Milodon, the old pan has a hard time sealing properly and I’m tired of messing with it! Accessory mounts were the biggest challenge, but if you’re not running A/C and only need an Alt and PWS, that shouldn’t be too much of an issue, I went serpentine to address my stuff.

jnb5101

i just dropped the 427 into my 70 today. i know it shoud be a 454, but i used what i had. i mounted the clutch and bellhousing and fuel pump while on the stand. two things, first, leave the valve covers off-they will interfer with the brake booster and the wiper door actuator, and second, adjust the load leverer so that you can drastically drop the rear end of the motor. a few tense moments working alone, but alls well that ends well!