View Full Version : 1970 Firebird Hood Clearance with Carbed LS1

08-07-2006, 09:01 PM
I am planning on doing a carbed LS1 conversion on my 1970 Firebird. I am just wondering how much taller a LS1 with carb and intake would be than a stock Pontiac 400.I really would love to squeeze it all under the stock hood but I have my doubts.

Can anyone give me a measurement of how tall a LS1 is from bottom of oil pan to top of carb?

Thanks guys!

08-08-2006, 12:49 AM
I'm doing a similar swap in my 81Z. Some trial fitting and it doesn't look like it will fit under the stock hood. I'm using S&P mounts. I'll have the engine in soon and then I'll find out if I need a new hood.

08-08-2006, 10:29 AM
Mine fits fine under my 2" cowl induction hood on my 67 Chevy II. I'm even using a 2" tall 14" air filter that sits above the throttle body (or carb in your case).

Do a shaker hood!


08-08-2006, 12:52 PM
It is looking like a shaker hood is what I may have to go with. I dont think a cowl hood would look right on this 2nd gen bird..

08-08-2006, 12:55 PM
I Have A 71 Formula Firebird With The Dual Snorkel Formula Hood And Man It Is Hard To Even Get A Regular Carb Under With My 400 Big Block

Phoenix 5.7
08-08-2006, 01:12 PM
can someone get a measurement from the crankshaft centerline to the top of the intake for both the 400 and the ls1? that is probably the easiest measurement to take and compare.

i want to do a 1970 T/A clone with a LS1 eventually, but i want to attempt to use the shaker hood

08-08-2006, 02:23 PM
Hey Phoenix I Will Give Ya My Firebird With An Ls1 For Your 99 Ss

08-09-2006, 12:40 PM
If anyone could help me out with even a measurement for a carbed LS1 it would be great!

08-09-2006, 01:03 PM

On mine, using a GMPP intake manifold and Holley 1000 cfm throttle body, it is about 7.25 inches from the valley cover to the top of the "carb" (where the air cleaner sits). From there my air filter is another 3.25 inches tall. In all, 10.5 inches from valley cover to the top of my Moroso 14" air filter assembly.

Different filter bases can be had for different heights too.

Hope that helps.


08-10-2006, 09:23 PM
Thanks for the measurements JP!

Is the GMPP a single plane or dual plane? Which one is better, Edelbrock or GMPP?

08-10-2006, 11:15 PM
GMPP is a single plane. The Edelbrock is available as either.

I can't say which is better ... but I can say I know the fellow who designed the GMPP piece, and I know they spent considerable time on the dyno with it. I'm running the GMPP ...