LT4 / T56 Super Magnum install into 57 Bel Air Sport Coupe

[FIVE7]

Appreciate any advice on LT4 / T56 Super Magnum install into 57 Bel Air Sport Coupe.

Immediate question: does anyone have experience with this install and know whether the firewall will need to be recessed or modified extensively? Adjustable motor mounts enough?

I've seen pics of LT4 installs in 57's and have also seen myself an LT1 where the firewalls did not appear to have been modified. However, I've heard from a couple of folks that the firewall will need to be recessed. The current firewall is already cleaned up nicely and painted so would prefer not to have the cost to rip it out, purchase a recessed firewall, install, repaint etc. See attached.

The frame, suspension, brakes, metal, body and paint are complete. The GM Connect and Cruise engine/trans is scheduled to ship on 12/29/23 (but has slipped a month since ordering mid November).

I believe I've found solutions to the general items needing attention, such as: fuel pump/tank, engine mounts, cross member, oil pan, power steering pump, exhaust manifolds, but all comments and suggestions are welcome.
And in the event anyone is interested, here are some additional details: I've had the car since 1977 and am doing a nice restomod. The plan is for a fully restored but stock body and interior with big upgrades in suspension and drive train.

Upgrades to date include:

9" Currie with 4:11 gears
Frame has been upgraded with the Summit Racing upgrade kit
Heidts four link
Tubular front control arms (adjustable Heidts coil overs all around)
Sway bars front and back
Everything powder coated black
Wilwood 12" and 13" brakes
Borgeson 600 Power Steering Box
Metal, body and paint work complete (stock Matador Red)
Body on Frame with all new hardware bushings
On order: LT4/T56 Super Magnum Connect and Cruise: Engine 19431955; Controller 19433248; Trans install kit 19329912; Transmission 19352208

Attached is a picture or two - lonely, waiting for it's drivetrain!

[WagonCrazy]

You've got a very nice build going there.

I can say that you're probably going to need to cut your firewall and for sure your trans hump to get that t56 to fit in there. I had to do extensive mods to my firewall and trans hump to get the LS1/t56 trans in mine. That transmission is a bit taller than most.

And you will want to consider an aftermarket shifter handle (for the front shifter position) that has the curve it it to work with your bench seat. The t56 trans has 2 possible shifter mounting locations cast into it, so you can mount one more forward (for a bench seat) or in the rear (for bucket seats).

Look in the Member Project Updates subforum, and look for my write up on mine called 57 Nomad-C4-LS1 called "Ozzy" There are alot of pics documenting all kinds of issues I've worked thru with the upgraded suspension and drivetrain.

[markm]

I have a TKO-600 in my 55 with a 396 and a tunnel ram, zero mods to floor, hump or firewall. Other than the hole for the floor shifter.

[chevynut]

Highly likely you'll have to raise your transmission tunnel for the T56. I don't know much about the LT4 (I assume the new direct injection LT4) so I can't tell you if the firewall needs to be modified. I'd try dropping the engine/transmission in the car and see what fits.