What Holly carb should I get?

[Britt]

Well, Ive had to put the stang on hold for a while, but im back and building an engine. Ive got a 302 im building with E7 heads and flattop pistons. Ive got a comp cams 280H magnum cam and a duel plane high rise intake.

I was going to get a 600 double pumper, but Im not shure. I want decent gas mileage but I also want optimum performance. I want snappy throttle response and good smoothe opperation.

Ill be running a C/4 auto

Im open to educated opinions and responces.

 

[slapper]

650cfm Vacuum secondary model 4160 will give you snappy throttle response and good smooth reliable street operation.

 

[thehueypilot]

I agree with the last thread.....600cfm 4160 elec. choke would be a better street carb. Double pumpers are more for the manual transmission crowd.

 

[madbrad]

On my 302 i went from a 600 Vacuum Sec to a double pumper same cfm adn noticed a difference in the acceleration. The VS was a lot better fo my car. Once i got moving i couldnt tell a difference either.

 

[65 project]

On my 65 GT, I went with the 570 holley avenger with the electric choke. If your HP is over 300, then you will want to go up to the 650.

 

[foghorn67]

go with the street avenger. it's a 4150.
don't get the 4160. it has a secondary metering plate and only 2 idle jets.
it doen't take much to get a 4150 idling smoother then a 4160.

also, mechanical secondaries would be a waste of gas with your trans.

 

[Britt]

Thanks for the replys.

I didnt want to spend all that much (not over $300 dollars). I thought all 4150s were double pumpers. I just want a basic carb that wont cost alot and I can tune and modify easily. I want a good performing carb and something that want waste gas for no reason.

Also, cant I get a 4160 and also get the kit to make it a 4150 with vac seccondaries or is there a carb in their line that already comes like that??

Thanks again. I realy dont know all that much about the holly line.

 

[Max Power]

You can call Holley and they will give you a recommendation. I think you may be running a little too much cam.

Also, if you keep the C4, remember to get a carb with an automatic kickdown lever.

 

[Britt]

Why do you think Im running to much cam?

 

[Ronstang]

Why do you think Im running to much cam?

What stall converter and rear gears are you running? Then we will know if you have too much cam. If you are running a stock converter and the 2.80 gears in the rear then you definitely have too much cam.

 

[Britt]

It said I could run a stock stall, but Im working on getting a better one anyway. The gears will be somewhere between 3.80 and 4.10. I put alot of reaserch and time in making my decision and I think I made the right one. If I picked the wrong cam, I will be the first to know, belive me.

BTW, since when did this thread become cam related???

 

[LMan]

have you read this excellent site? It may help you in your research.

http://www.bob2000.com/carb.htm

 

[67GTA-FB429]

A 600cfm Holley would be plenty. Maybe even the 570cfm. You can calculate your maximum air flow needs via;
http://www.classictruckshop.com/garage/shopmathcfm1.asp

Here is a link to a carb. http://www.holley.com/HiOctn/ProdLine/Products/FMS/FMSC/0-1850C.html

 

[67yellowcat]

Hi guys,

Can someone explain why a double pumper is better for a 4sp car than a vac secondary would be ? I've got a 4160 on my 4sp car an am wondering what advantages I might see with a 4150 dp ??

Thanks,

John.

 

[LMan]

If its a mostly-street car, I can predict a serious decline in your gas mileage, unless you tune/tweak it to the nth degree. IMO, regardless of transmission, a DP is best left for the track where fuel economy is irrelevant.

 

[Ronstang]

BTW, since when did this thread become cam related???

Well, an engine is a package and should be treated as such. Every part you choose should compliment the others and thus even a small change could have a ripple effect. The cars that run the best are those that have very carefully planned out drivetrains with a purpose in mind. A lot of vehicles are merely average because people tend to use what they already have or have easy cheap access to.

Anyway this is exactly what the Competition Cams catolog says about their Magnum 280H cam:

"Broad Power. 2500 stall, low gears, 9.5:1 & headers. Rough idle."

I'm in no way trying to bash you I am simply trying to help you maximize your performance/$$$. I have been building these cars and making mistakes for 25 years and have learned a lot along the way. Your car will run with a stock C-4 stall but you will have to idle it quite high to keep it from stalling and it could quite easily bog a little off the line but the low gears you are going to be running will help alot and will mask the problems with the stall to a degree.

I was in this exact situation with my Shelby. I have a very similar cam albeit mechanical and with the 3.89 gears it ran quite well but it had to be idled at 1100 RPM in park to not die when put in gear and the 1-2 shift was so abusive that it bent my crossmember and passenger side motor mount saddle a little....and it squared out the holes in the back of my driveshaft. I switched to a 3000 stall and the car is totally different now (but if I had to do it over I would have gotten a 2500 stall but the guy that built mine used a formula to choose).

Oh....the carb....get a 600 0r 650 vacuum secondaries and down the road you can get the secodanries metering block kit if you need the adjustability. Go ahead and get the secondaries spring kit right away to fine tune the secondaries and the car will run very well. You don't need any bigger of a carb and I know quite a few people running in the 12's on a 600 cfm carb.

 

[65 project]

There was a Dodge dealership selling new Holley Avenger carbs on E-Bay. The 570's were going for under $300.00. That's where I picked up mind. I don't know if they are still selling them, but it was sure a good price. Use Holley avenger for the search.

 

[geegee]

Thanks for the replys.

I didnt want to spend all that much (not over $300 dollars). I thought all 4150s were double pumpers. I just want a basic carb that wont cost alot and I can tune and modify easily. I want a good performing carb and something that want waste gas for no reason.

Also, cant I get a 4160 and also get the kit to make it a 4150 with vac seccondaries or is there a carb in their line that already comes like that??

Thanks again. I realy dont know all that much about the holly line.

I use a Holley Street Avenger 570cfm atop a Weiand Action Plus dual plane manifold (low rize, dual plane, idle to 6000 rpm bandwidth). Its a good match and was easy to tune. Basically it worked right out of the box. I did re-adjust the float levels because they were a bit high. I adjusted the mixtures to high rpm idle roll off as suggested in the accompanying literature and its been running like that ever since with no further tinkering.

Cost was $285 (mail order).

 

[thehueypilot]

The question concerning the differnce between a DP and a vac secondary vs type of transmission is a confusing issue. I may be wrong but I believe a DP was designed first to complement the manual transmission. When you romp on the gas it squirts fuel into both the primary and secondary side. If you think about this when you are manually shifting you are stepping on the gas and letting off the gas when shifting which helps to eliminate the bog after romping on the gas again. The vac secondary with an automatic does not experience this continuous gas pedal stomping effect so the diaphram opens only to the need of the engine thus better fuel economy. I think.....?

 

[67GTA-FB429]

There is no secondary side accelerator pump on a vaccum carb. Two accelerator pumps, that is why it is called a double pumper.