In this interview, we talk to Keith Petelle from High Velocity Heads​ about selecting the right carb spacer for a GM604. You can see them all at: https://crateinsider.com/brands/High-Velocity-Heads.html

Full Transcript:

I'm Kate with Crate Insider.com and I'm here today with Keith Petelle from High Velocity Heads and Keith and I have been working together really since the start of Crate Insider with his carb spacers. And now Keith, with your carb spacers, tell us about the different options that you have when it comes to the GM604.

We've actually got four different options for the 604. The first one would be the best and our biggest seller right now which is for E-85 and methanol. This SS4150-1DPAL and it is legal for IMCA and some other classes, but make sure that you check your rules before you run it because it is illegal in some sanctioning bodies. Basically, what it does is create more torque in the motors running E-85 and methanol. Gets you off the corner better, accelerates better, so even though it's not increasing the top end power, it still gets you around the track faster.

The reason it's not necessarily legal in all series is because I understand that half of this spacer projects into the intake manifold. Correct?

That is correct and that is against the rules for some of them, but that is also what decreases the plenum volume of the manifold and helps increase the torque.

Excellent. Great! So what are our next selections that we can look at for a 604?

Another selection for the 604 would be the SS4150-.5AL. It is also another great option if you're running E-85 or methanol. It also increases torque and is legal in all of the series because the limit in most series is 1" tall, but you can go shorter than that. The other one would be probably one of the more popular ones for the 604 is be the SS4150-604. And that one seems to work well on short tracks, long tracks. It also helps increase torque. Which works on racing gas, oxygenated fuels, that sort of thing. And another very popular one is SS4150-1ALW, and that one also works well with oxygenated fuels. Some people claim that this one it makes the most torque. It's kind of a mix between the feedback we get so sometimes it's good to try different spacers for different applications.

That's fantastic. I definitely learned something today from this. So let's just kinda recap. Obviously we talked about this one as a separate deal, but if you're on a really short track, what would be the one that you would recommend, or is it really fuel dependent?

Right now it seems to be fuel dependent. Obviously shorter usually shows more torque. I have some customers saying this for oxygenated fuel is showing more torque and like I said I get mixed feedback, but for the most part the shorter you go the more torque you make.

Well thank you so much Keith. Obviously it's a pleasure we've been working together for a long time and you can check out all of the HVH spacers right there on Crate Insider.com and if you have any questions feel free to give me a call.

Thanks.