As I sat thinking of a cam for my set up I started to wonder what if I had changed the firing order a little I was think of swaping 4 and 7. Then I go looking to see if anyone has done this for the lt1 but no one has. They have it for standard chevy. Would there be any advantage of having a cam ground like this. Any one pick up more power this way.

 

If there would be an advantage, GM engineers would have done it already! Why would you want to do that anyway?

 

All in the name of power, i want to get ever ounce of it out of this motor. I dont think gm changed the firing order from sbc to lt1. So If I can gain power just by swaping two cylinders why not. It should cut down on crankshaft deflection. As for power to be gain by doing this I dont know.

 

I don't think it is possible. You would have to change your crank too, and I don't think anybody makes a crank like that.

 

Sounds like a lot of work for nothing. Just my .02

 

no change in the crank, it possible All you would need it the cam and change your spark plugs around.

 

How are you going to convince the pcm that you have changed the firing order (like for injector timing)?

 

Cut the harnesses off of each and run the wires over to each side.

 

I like these kinds of discussions. . .

GM changed the firing order on the LS1's. To what? 4/7 swap and 3/2 swap.

Guess what the 302 Ford (1988 and up) firing order is (once you number the cylinders PROPERLY)? Same as LT1/SBC except 4/7 swap.

Both Comp Cams and Lunati are now offering 4/7 swap cams for for Chevy small block V-8's.

However, a local dirt track engine builder has been doing this for 3 - 4 years. Comp and Lunati only started this year.

The dirt track engine shop reported gains of around 12 - 15 hp on a 650 hp, 7,500 rpm SUPR motor.

Mike

 

i also have heard about this...i guess if you had a 93, which i think is batch fire, you wouldnt have to worry about injector timing.

 

Wrong. It still wouldn't work.

 

so what your sayin is the 4-7 swap would gain somethin, I dont mind a little fabricating, I was thinking on the lines moddified wiring harness. hmmmmm do you why exactly, I know it produces a little less friction, less stress on the crank but there has to be somethin else to why this is so effective. Do you know if there are gain though the whole power band or just in the upper rpms?

 

If yours is sequential injection, I think it would help to run the #4 wire to the #7 and vice versa. Keep in mind that the + is constant, so the - would be the only wire to switch cylinders.

You'd also have to swap the spark plug wires, which is probably a little harder than is sounds due to the Opti.

It probably gains power due to crank to cam/spark phasing. They do this swap because is stresses the crank less, so it will flex less. This means cam and spark timing events would occur closer where they were meant to be.

I would expect the 4 - 5 rwhp you'd gain to be only up top. Keep in mind that the motor that gained 12 - 15 hp was a 650 hp 7,500 rpm motor on the engine dyno, so the gains you'd see at a lower rpm on a rw dyno would be much less.

Mike

 

Im going to try it. The way i look at it wether its 1hp or 50hp gain it still makes me go faster. most likely I want to shift my car at 6900 anyways so I should see pretty good gains. Big cam 245/259 112lsa

 

Pleeeeeeese tell me you're not attempting this with Edelbrock headers and a FlowDisaster muffler. . .

Mike