was watching HorsePower on Sunday and they were dynoing a LSX engine and after they dynoed ut they added a carb spacer and they gained something like 20 Hp. I was wondering if I added a 1" carb spacer to my '65 425 with a Holley 750cfm vac secondaries, performer intake, and dual manifolds with a 2 1/2 exhaust would it add any benefit?would I gain any more power? torque? also which would be more beneficial open? or 4-hole styled?




Thanks

 

I don't think you would see much improvement. The problem with those articles is that they only show one application in extremely controlled conditions and leave the readers to draw a conclusion about their vehicle. Many times I think they simply encourage consumerism whether the product purchased really gives a benefit or not is questionable. Did they say why they added the carb spacer?

 

Go with the duals first...headers would be better, but duals will definitely
make a difference you will probably feel.

As far as the spacer...they're not just bolt on and go. The second you
alter your carbs position you will change the 'signal' going to your carb.
Spacers are not gimmicks and they usually are good for some modest
gains. But you should re-tune your carb to take full advantage of one.
(now if that $30 bucks is burning a hole in your pocket, you could ad
it and see if works without retuning...weirder stuff has happened.)

I think my engine showed a 7 hp increase with a 4 hole.

 

I already have the duals and such, but I was just curious if a spacer would be beneficial for me to buy. I think I'll buy one and see what happends

 

The first problem is where in the curve was the 20 HP added. The problem with virtually all dyno tests is that they only show peak HP. This is fine for a dragstrip motor that only operates in a narrow RPM band, but for a street driven car what you care about is the area under the HP and torque curves. A 20 HP boost at 6000 RPM is of little use if a) you rarely run at that RPM and b) it brings a 20 HP loss at 2000 RPM.

A spacer CAN help, but as with most mods, it depends. If, for example, you have a dual-plane intake and want to boost low-end torque, then a four-hole spacer MAY help by increasing effective runner length, but at the expense of top end. Similarly, if you want to increase high RPM power, an open spacer on a dual plane intake can often help by letting both sides of the intake "see" all four barrels of the carb. This improvement will come at the expense of low-end torque. The bottom line is that any engine configuration is a tradeoff between low-end torque and top-end HP. And to complicate it further, each engine is different, so this is usually a cut-and-try operation. Without a dyno or track testing, actual gains are hard to measure by the seat of the pants, particularly if the wallet in the pants is lighter due to the mod and you are "incentivized" to see a benefit from the mod.

 

It will be a street driven car, and I will see if there is any benefit to using a spacer, it will give me an excuse to drive the car more.....lol I understand the trade off and whether or not any real benefits would be gained, but it won't hurt to try it, since I've never ran with one before.

Thanks