Has anybody ever had the firieng order on and LT1 changed. My brother is doing that to his 540 bbc and claims just that change is worth 40hp. Just wondering what increase in HP an LT1 could be achieved and what is involved in doing it?

 

You could change the firing order, but you'd need a special camshaft. LS-1 and 8100 have the "new" GM firing order which reduces some torsional loads in the crank maybe 7%. GM doesn't claim any power increase.

As for a hp increase, especially 40 hp...IMO, that's blowing smoke.

Now if he were talking about a 180* (flat) crank, and all of the tuning, cam timing, etc. which goes with it, I could believe maybe 40 hp on an 800 hp BBC....maybe.

Just a wild guess here: you're brother is not a well know engine builder, is he?

 

The guy who is building my brother's 1300 hp motor builds pro stock motors.

 

Ok, at the 1300 hp, NA level, there might be 3% or 40 hp from any number of things. At that level, valve spring choice can be 40 hp or more, as can a few degrees of cam timing. Pro Stock engines (500 cubes ~ 1300 hp) are some of the most highly developed, sophisticated NA engines anywhere. They are also very expensive.

How much money is the builder quoting just to change the firing order, and why did he say he wants to do it?

Mechanically there is no big advantage if you are staying with a 90 degree crank. Some PS builders may have gone that way and have access to cam blanks for different firing orders, or even flat cranks. If the top guys are doing this, they aren't saying much about it, but do they ever?

As far as doing it in a LT1, even if the hp/cube remains the same, and there is 40 hp @ 1300 hp level, that's about 12 hp for a 400 hp engine. I'd guess the cam would be very costly, however, unless the special blanks are readily available. IMO, there are less expensive, well proven ways to pick up 12-15 hp.

My $.02.

 

It has been done. But no advantage to sepeak of on the dyno or track testing. If you want to talk to the guy I can dig up his e-mail I know I have it some were. But honestly he said he has seen no gain from it!