LT4 Vs. LS9

[colorado80439]

Originally Posted by Spiffav8

What happened to the 69 LS7 build? Wasn't it in paint late last year?

OMG the 69 it's still in paint, should be sprayed in the next week or 2, it's been in paint for a year now, there's only 1 paint and body guy (who is excellent) at the shop and he keeps getting pulled off my car for other small projects.
I've just started a 67 now leaning toward a RS fast track chassis with an LS9. Currently discussing fitment with Roadster shop, as always issues and compromise w/ engine clearance, FEAD systems, track width, tire, wheel size and set back

[colorado80439]

Originally Posted by srode1

As far as fitment the LT4 high pressure pump will mean you probably need to modify the firewall for clearance, for the pump and the electrical connections. That's the price of direct injection vs port injection. I'm sure you've read the other technical differences and that the LT4 has more torque earlier making for a flatter power curve too which is an advantage in any application IMHO. The wiring on the LT4 isn't really complicated, just plug stuff in and it works and it's gone in lots of cars so there's plenty of information on front runners.

Thanks for the insight, I've enjoyed watching your build

[colorado80439]

Originally Posted by rpol78

My understanding is you have more ECM options with the LS and more options for making changes. I do like the LT4/LT5 engine with the direct injection. It just depends on what you want to do in the future.



Hmmm... Makes me wonder what my LS 396 engine is worth (LS9 block/LS9 CNC heads, Callies Magnum custom crank, Callies Ultra rods, JE custom pistons, Kong 2650).

FWIW - This is going in a '67 Chevelle.

Very nice, Kong 2650 LSA blower on an LS9, with a dedicated SC pulley who's front runner is that?

[rpol78]

Originally Posted by colorado80439

Very nice, Kong 2650 LSA blower on an LS9, with a dedicated SC pulley who's front runner is that?

Thx, It's the GM modified LSA accessory drive 19417908. It has the same spacing as the corvette accessory drive with the LSA SC pieces added to it. Unfortunately it doesn't look like it's available as a kit any more.

I ended up having to use the Holley A/C compressor mount with a Sanden SD7B10 since I couldn't get a GM compressor to clear the main cross member. I'm still trying to work out the A/C lines on it.

[colorado80439]

Ended up going this direction