Mock up engine block question

[E84MC]

So my next task is to get the car painted with firewall. I want to drop an ls3 with a T56 in it so I need to make some cuts to the tunnel. I’ve read that all gm engines back to the SBC 350s have the same bellhousing bolt pattern. My main questions are, will an ls3 t56 bellhousing even fit a SBC (actually have the stock 305) and if it does will there be any differences in engine placement weather it’s height or front to back location of motor to that of an ls?? Don’t really want to get the ls3 and have it sit for a long time plus I can use the money for paint. If my 305 block works I would want to use it to mock it all up and if it doesn’t I can get a genIV 4.8/5.3 block for cheap and use that instead, maybe that’s even better as I’m pretty sure all LS based motors are the same as far as the block, right? Thanks for the help in advanced.

 

[pontiacgp]

 

[ssn696]

The bell housing bolt pattern is physically the same, with one bolt missing on the passenger side. In order to mock it up this way, you are committed to have the LS match that interface location. There are motor mount adapter plates that move the LS block position to match the SBC location. That’s what you’ll have to commit to when you put the T56/T6060 trans in that location and tweak the floor pan to match.

 

[Northernregal]

What mounts are you using?

 

[Streetbu]

Don't try to guesstimate the position of your LS, using a sbc. You'll regret it later, they (the LS) run close to the firewall and heaterbox.. even find a junk LS block for mock up.

 

[E84MC]

What mounts are you using?

I have the gbody Holley ls swap mounts now.

 

[E84MC]

Don't try to guesstimate the position of your LS, using a sbc. You'll regret it later, they (the LS) run close to the firewall and heaterbox.. even find a junk LS block for mock up.

Yeah that’s what I was wanting to do but was making sure. Forgot all about the ls engines being closer to the firewall with these Holley mounts!, thanks!

 

[E84MC]

So a 5.3 from like a 07 and above truck will work fine for mock up before I get the ls3 right? Just want to be sure because I’ve screwed my self before on other calls!🤦‍♂️

 

[fleming442]

LS swaps are cheap and easy!!

 

[Streetbu]

So a 5.3 from like a 07 and above truck will work fine for mock up before I get the ls3 right? Just want to be sure because I’ve screwed my self before on other calls!🤦‍♂️

Yes any LS block will work fine