big block swap
Thread Starter
Pro
Joined: Sep 2012
Posts: 600
Likes: 6
From: Key West Florida
big block swap
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
Last edited by 1977L48; Jan 6, 2014 at 09:01 PM. Reason: cam specs
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
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!!
Melting Slicks
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
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
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
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 416
From: N J
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 $$$ into an aluminum radiator instead. The stock booster can probably be used but I used a new smaller one. Good luck with the swap. I had a lot of fun doing mine and I really love driving the car now.
To help keep the cost down, I didn't use any corvette big block acc brackets or pulleys. Went with a long WP and put the alt on the right side, not above the ps pump. Plenty of room to work. Put that $$$ 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.
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 416
From: N J
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.
Last edited by John 65; Jan 7, 2014 at 03:08 PM.
Racer
Joined: Nov 2008
Posts: 366
Likes: 7
From: Mobile Al
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.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
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.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
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!