[hiimed]

I have a '49 Chevy Truck with a basically stock 350/350 engine trans combo with a Camero rear end. I've been running a Edelbrock Torker manifold with a Holley 600 carb with an eclectic choke. This is my daily driver and 99% of my driving is on surface streets under 50 mph. I've read that cooler fuel is denser and gives more top end power but I've also read that warmer more vaporized fuel gives more bottom end power. Is any of this true? I'm switching over to an Edelbrock Performer manifold this weekend. I'm wondering: Do I want to block off the exhaust port that would normally go the choke, or do I want to leave it open to heat the manifold? Like I said, I don't normally go over 50-55 but I like to get there in a hurry.

[DoubleVision]

It`s a wise choice to go with the performer, a torker isn`t needed for everyday driving. In the climate you live in, I don`t think the heat risers are really needed, I don`t know what kind of winters you have out there, but I know the summers are hot, you could just add restrictors and be okay.

[Jmark]

Greeting Hiimed! Another Phoenix person here.

I have the Performer on my truck and use the restrictor insert that comes in the Felpro gasket set for the crossover passage. The opening is about 1/2" in diameter and seems to work fine. The winters here are not killer, but we see 30 and sometimes less here so having some carb heat is a good idea, atleast in my book.

My son chose to block his off completely and regrets it now. This past winter, his truck was very cold blooded for a long time, until some engine heat finally made its way to the carb.

Just my 2 cents, which these days, doesn't go too far! LOL

Mark

[hiimed]

Thanks for the input. The gasket set I have has 1/2" holes but I have a set of metal plugs that were left over from my son's truck and I was just wondering if I should use them or not.
Mark- do you go to any of the Friday or Saturday car shows? Maybe I'll see ya there.

[lluciano77]

I would block them off completely. Just adjust your choke to make up the difference.

Cooler, denser air/fuel will make more power in all RPMs. Warmer air/fuel will make less power.

[61ChevyTruck]

wouldn't leaving that open create a huge vacuum leak???

[hiimed]

61- The manifold has a plate blocking the hole where the choke linkage would go.
Anyway it wouldn't be a vacuum leak, it would be a huge exhaust leak if that plate wasn't there.

[hiimed]

I just installed my performer manifold today and what a difference from the torker manifold. I still have some timing issues and want to play with the jets a little. Other then that, there is a definite difference.
The gasket that I used didn't have a hole in it for the exhaust after all so I cut one in.
Thanks to everyone for the help/advice.
Ed

[lluciano77]

I have read that plugging the exhaust crossover on most small blocks will make 15 to 20 more hp. And that the warm up time difference is negligible.

On Pontiacs it can make almost a 40 hp difference.

I would keep the stock jetting in the 600. I bet it is right on the money. The funny thing about smaller carbs is that the smaller they are for your engine, the richer they run.

A bigger, more powerful engine will pull more air past the carb. This richens things up. So when an engine has a bigger carb, sometimes sometimes the carb needs a couple jet sizes more. With a smaller carb the same engine may be able to get away with stock jetting.

Most people I talk to think that in order to run a bigger carb on a smaller engine you need to jet the carb down. Or the opposite for a small carb on a large engine. That is not the case.

[hiimed]

I've noticed that the truck seems more responsive when I first start it up. I'm assuming that that's because the carb is choking and it is running richer. I could be wrong but that's my theory.

[hiimed]

Here's a picture of the install. I think it turned out pretty good.

[killerformula]

that's one heck of a carb stud, how big is your aircleaner?!

[hiimed]

It's for a K&N velocity stack and sometimes a spittoon.