[slick mo fo]

Just got the 351C rolling last week, Took it to the Dyno shop yesterday for a good tuning.

351C .030 over 4 bolt mains, rv cam (.281 int. &.296 exh cam lift) 4V quench heads, C6,... intake (600 performer and performer intake) they put in the largest jets they could, but say it's still lean. they recammended a Holly 750 (p/n 80508)

Dyno readings;
top RPM 5000, 240 hp at the back wheels and the torque was good and flat at 250 lbs all the way thru.

they didn't speak to highly about the road deamon or the Edelbrock, I'm thinking about getting the Holly and possibly the Victor Jr intake.
would this be a good combo? daily driver and will see the track from time to time.
also how much will this combo give me? (power wise and RPM range)

 

[Hottarod]

Well something sounds strange about the carb situation. A carb controls the cfms of air the motor gets and the jetting regulates the amount of fuel that is mixed with the air. They should have had no problem properly calibrating the jetting for that carb. A 600 cfm carb would run fine on the motor up to the rpm point that it ran out of air flow and then the motor would start to fall over because it wasn't getting enough air to sustain its rpms.

At any rate the 750 will only improve things on the top end of your range. If, for example, the motor would like to run on up to 7000 rpms but the 600 cfm carb will only supply air up to 6000 then the 750 would give you the other 1000 rpms and let your motor see the rest of its power curve.

Carbs don't make any much more power except in cases where a carb more efficiently mixes the fuel and air(downleg boosters and annular boosters for example are more efficient). The carb just allow the power that is in the motor to come out by supplying it the air and fuel it wants.

 

[slick mo fo]

Aaaaahhh, pretty much what I was guessing, seeing how the stock carb was like a 450 autolite. I think what they were getting at is for me to get to the 6000 mark that I want, I would have to go to the larger 750. they said they put in the largest ports they could get for it.

either way the 600 isn't going to get me whare I want, in the time I want......
-------------------------------------------------
more air + more gas = more fast

so should I go with the Holly 750 for $270, or the Holly Street Avenger 770 for $380? for the $110 are they that much better? and what kind of intake? stick with the Performer?

 

[Brian M]

I ran a 600 on my 351c, but when I went to the 750, I noticed it much peppier, and seemed to go a bit quicker. Probably was because the 600 was old and crappy, and the 750 was brand new. I havent had a problem with the 750 at all, runs well. I would say if your 600 is an old carb, get a new one. If it is a fairly new carb, keep it, and figure out what is wrong, if they have to jet it to the max, and it still runs lean you have some big vacuum leak somewhere.

 

[slick mo fo]

the 600 is fairly new (couple years), but it's not giveing me what I feel the cleveland can or should be putting out, it still runs great, freaked out my old man.

at WOT it's pulling 1.5" of vaccume when it should be at "0". no leaks, checked that.
what brand of 750 did you put on? don't you have the 2V heads?

 

[Mach1Morgan]

It's not possible to have "0" inches of vacuum at WOT. The velocity through the carb at anything near "0" vacuum would be so low that the carb wouldn't function. To get the best power over a wide range you should be shooting for .9 - 1.2 inches of vacuum at WOT and your highest RPM. The 1.5 inches of vacuum is probably costing you 15 or 20 HP on top end. Also, Edelbrock doesn't make a Vic Jr for the 4V Cleveland. For the best torque and power in the 3000-7000 RPM range the Blue Thunder intake from Probe Industries is an excellent choice. If you want power from 1500-5500 RPM the Edelbrock Performer 351-4V will work great.

 

[slick mo fo]

seeing how I drive in So. Cal stop and go traffic, I should stick with the performer. When I invest in the 7000-8000 RPM's I will be going to a tunnel ram w/ dual quads or blower.

How would the Holly 750 with the performer, work with a shot of N2O? or would I need to upgrade the intake?

 

[Brian M]

I have a holley 3310 with the shiny finish, my 600 died and I had to have my car workin by the next day, so I grabbed the only 750 that was in stock, vac secondaries, manual choke. I would really much rather have the electric choke, the stupid cable doesnt work hardly at all. I have 4v open heads, no cam yet, but I have the crane screw in stud kit installed, with harland sharp rockers. Works great, but a bit louder than stock (i might have a lifter problem as well) I also have a edelbrock performer intake, not worth it, I hardly noticed any change from the stock aluminum one I had. So far the most seat of the pants change was when I put the 4v open heads on, it had 4v open heads, but had sticking valves, and valves that werent sealing right. The new one gave quite a bit of power, haven't dynoed it yet, but it just felt much better. The next improvement was the moroso underdrive pulley. I bought it used for a good price, wow what a difference. Only notice a problem on very hot days (over 95-100) and only if I am sitting for more than 15 or 20 minutes, the temp guage creeps up. My ammeter shows that the alt doesnt charge at idle, but I have had it like this for months with no problem, who sit and idles all day anyways