ok here is the mods,650 dp 4150 jeted 69 84 rpm intake 350 .30 over dart iron egale heads 215cc intake runner 64 cc combustion chambers 1.437 duel springs 2.05 1.60 valves comp cam 274, 230 236 @.50 and 4.88 4.90 lift 1.6 roller rockers hooker super comps full lenth 1 3/4 part number 2210 msd pro billet dis with msd 6al and blaster 2 coil and 4.10 gears best et in the 1/8 is 8.2 at 93 mph with 2.10 60 ft, so what do you think guys would it help me to go with the 750,and if so how much would it help,,,,,,,,,,,,,,,,,,,,,,thanks

 

Per Holley's recommendations, a 650 will support a 355 ci to 6300 RPMs. Having said that, conventional wisdom will say, "Get a 750."

FWIW, Holley also says a 750 DP won't kill a 355 as long as RPMs are above 1500 when you nail it.

Personally, I didn't notice much of an improvement going from no-choke Holley 650 DP on my 401 (.030"-over 396, 5600 RPM shift point) to the 750 Proform main body - about a tenth in the quarter at most.

I got a lot more improvement going from VS to DP, going to a higher stall converter, and setting up a cool-air induction system vs. open element.

 

thanks for the info,doesnt sound like its worth the hassle then,ill just leave it as is,

 

Doesn't mean I don't like the Proform. I do. It's only $100 vs. $400 for a 750 DP, even more if you want the features the Proform body has. I do have 46 more cubes than you do, though, and I've got "dreams" that the 750 will need to support.

You do lose the timed vacuum port, which I forgot when I installed the body.

 

well i think the 650 came with 67 71 jets i had to jet it at the strip,best et was with 69 84 thats a lot of jet,so i thought if i uped the cfms with the jet,it would help

 

Just to give you an idea, when we engine dynoed my motor, we used a worked up holley 800, and then my streetaveneger 670...

my street avenger 670 put out only 8hp less and 12ftlbs less.. considering that my carb is box stock, and the shop carb had 600 dollars of work done to it, thats pretty good. we ran the motor to 6900 on the dyno with both carbs, my carb showed NO signs of drop off in hp at top end (hp stayed between 431 and 432 from 5900-6500...

 

Peak HP & torque are only part of the story, however.

The fastest 1/4 mile MPH my car ran was with the 750 VS. But, that was .5 sec slower than the best run ET with the Proform, its speed being around .75 mph off the VS #.

 

so you picked up .5 second in ET just by using the proform body?

 

lol, no, as Paul Harvey says, you need to hear, "the rest of the story".

The VS was run with a 2200 stall converter and open element air cleaner. That's how I started the 2003 season, and ran until mid-July.

Going to 650 DP in July dropped 2 tenths.

Going Proform in August dropped about a tenth.

3500 stall in early September was worth 2 tenths.

Cool air induction and cooler weather in late September and early October took off another tenth.

It doesn't add up to .5 because I was only speaking of the best VS numbers. Comparing "typical" #'s, the VS was about .7 slower than my last runs of the season.

My point was the MPH, which is indicative of peak HP, was highest with the VS, during the summer months to boot, in spite of the other improvements which dropped ET at the end of the season. Cooler weather should have brought my MPH up, which it did, but still didn't catch the earlier VS #. I'll take the current ETs and consistency any day.

 

You've got a great power plant but kinda mismatched. Defiantley need bigger cam, your seriously depriving those heads with that peanut. Shoulda stuck to a smaller head and then that cam woulda shined, but not with the 215 runenrs. You either need a bigger stall or stickies since your 60's suck to be blunt. And once you get those issues resolved ditch the 650 and go wither 750 or 830 if this is for a drag racing application which by the specs it is.

Edit, just realized why you have no 60's, your heads are too big, cam too small, so you have almost no torque either downgrade your heads or get a bigger cam.

 

if i come out of the hole hard with the nittos it will brake the junk 10 bolt axles,its done it three times,if i run street tires it spins till it hits third,

 

I wish that's all I'd keep fraggin was axles. I have a serious knack for stripping the teeth off ring gears. I'm lucky I got abuddy that parts out these 3rd gens so rear ends were only $80/ea. but after this 3rd one, it's time to get the real deal this winter so I dont have this problem next season. This is with welded axle tubes and preload rear diff cover too.

 

went to the track last night it was 45 outside so the 60s sucked best et of the night was 8.0 at 94 mph in the 1/8 with 2.0 60 ft i dont no what that comes out to in the 1/4 but 94 mph is very good i think, if it hooked up i think mybe high 11s what do u think

 

More like 12.0-12.5 or so. You have the potential for 11's once you get the right carb, cam, heads that all work together. Real stickies would be my first investment so your not over estimating your "should be running" time with what your actually running and will also give you concrete ground to stand on when you start to improve your engine. Next investment would be larger carb, then when time allows get a better cam and you'll have a definate pounder.