Totally rookie question...

[kornball426]

So, tons of people ask this question... And I'm dying for an opinion so I'll break down and ask. How much HP and 1/4 mile ET do you think my car will do. It's got a Chevy 355 with Edelbrock Performer RPM heads on it 10.5:1 comp, performer RPM intake, 750 holley dbl pumper, pretty big Lunati cam don't know the specs, hooker comp headers, 3 inch exhaust no cats through flowmaster super 40's, 3200 stall converter in front of a TH350 with a full manual valve body (aka won't shift auto at all), with a 3.73 posi rear, to 265-50-15's. Car should weigh in somewhere between 3400-3600 lbs without me in it, no suspension mods at all I want to ad urethane bushings and caltrac bars.

I think low 12's ET, and Edelbrock advertises their one crate motor with a .480 lift cam, same heads and intake as mine... With 9.2:1 compression at 420 horsepower. I think just the bigger cam and more than a whole point of compression I guesstimate my motor makes 450-475. But what do you think?

 

[khan0165]

check out my signature for my specs... Sort of similar to your's, but more aggressive cam, and longer gears.

I'd say 12.7 @ 110mph if you run slicks... cuz you've got gears working in your favour. You'll see low 12s on spray, but not on motor... sorry.

 

[kornball426]

Well I don't know what cam is in it, but the guy that sold it to me said it's .510 or .525 lift which is all he knew, but it's got some lope to it so it makes me thing it's pretty aggressive. He said he had the motor built himself, but the castings on the heads say 2003 which would have put this guy in highschool. I only got the motor up to about 4000 rpm street driving, since I bought it but it pulls very hard. I bet he bought the car in the exact condition it is now that he sold it to me in. I'm dying to tear the whole motor apart, but I'm trying to keep saying to myself "if it ain't broke, don't fix it". It runs really strong, it burns rubber at will and has excellent oil pressure. So to me that means just repaint it and leave it alone.

 

[khan0165]

hmmm... I've only seen a few 355s run a cam that big for street use. Do you know if it's a roller cam? Rollers have big lift without big duration, so they are manageble on the street.

a regular flat tappet cam with that much lift probably has around 0.242 duration at 0.050 and likely pulls shitty vacuum at idle.

... that being said... if it's a 0.510 cam... it's a f'ing monster! Should be good to 6500-7000rpm.
in which case, yeah, I think you'll be in the mid 12s on slicks.

and I say slicks cuz..... my 12.9 car can barely break mid 13s on tires, cuz they just spin thru 1st and 2nd.

One thing I warn though..... just cuz your cam's good to 7000rpm, doesn't mean your rotating assembly. I don't recommend treading past 6500rpm unless you've 4bolt mains and a forged crank.

 

[FE3X CLONE]

a regular flat tappet cam with that much lift probably has around 0.242 duration at 0.050 and likely pulls shitty vacuum at idle.

... that being said... if it's a 0.510 cam... it's a f'ing monster! Should be good to 6500-7000rpm.
in which case, yeah, I think you'll be in the mid 12s on slicks.

.510" lift seems pretty mild. I know most of the camshafts (granted they were Olds camshafts) I've dealt with had profiles with 216/228 duration @ .050 but only .512" lift. Nothing radical at all.

My hydraulic roller has .595" lift with 242/254 duration @ .050".

 

[stomis]

.510 is not a radical cam even for a 355. Hell I'm going to be running a .504 cam after its corrected with rockers on my vortec 355 and I doubt there will even be a lope at idle.

Youve gotta be aware theres like 500lbs you could shave off your car. That would take you from a high 12 to a low 12 alone.

Id say with stock Edelbrock RPMs (because they have plenty of room for improvement with porting) and a .510 lift cam you should pull 12.80s at least. Depending on how well you drive and whether your on slicks you could vary anywhere from a 12.50 to a 13.xx.

I've seen videos of stock vortec headed 355 thirdgen camaros (which are the same weight range as our cars) go 12.55 on drag radials.

As for horsepower I'd say you more than likely could have achieved the same level of power with a vortec build but would gain some weight and also torque that route. My guess is your right in line with a well built vortec engines numbers just inverted horsepower and torque. Between 380-420 torque and 400-435 hp. Where as a vortec engine would be opposite.

The only true way to know is to take it out though.

O and btw I would say your car is highly over carb'd fyi. Probably needs a 600 or 650 cfm.

 

[jrm81bu]

13.5.

 

[84cutlass454]

13.20s

 

[JBreu]

Here is my combo:


388 stroker block built for 93 pump gas....

all forged lower end
eddy performer rpm cam : 234/244 ad.duration (488/510 lift) flat tappet
dart pro 1- aluminum heads 200 cc 2.02/1.94 valves
performer rpm air gap intake
eddy 750 carb (old) dynoed at 514 hp at 6800 rpm...I now have a holley 750 DP
700-r4 transmission 1800-2000 stall
4.10 gears

I ran a best of 12.57 @109 mph................

with the th-400 last year and eddy carb (with a bog off the line issue) and a 3000 converter w/3.73 gears my best was a 13.39 @103.

Both times weere with nitto drag radials.........however with the 13.39 time I had high tire pressure ( still hooked though)

With yout set up as is ..........low 13's to high 12's I'd say..... JMO though 8)

 

[kornball426]

Thanks for the opinions everyone.

Since the heads are said to flow 20% more than vortec's and their crate motor with less cam and less compression is advertised to make 420 (obviously that's crank, but false advertising is illegal... So you decided), and I know advertised not real world. But still, I would venture to guess it's more than 425 horsepower. I forgot to mention it's got 1.6:1 Comp roller rockers, and I'm not sure because like I said I haven't had the motor apart, but it's supposed to have a roller cam and lifters. It's also supposed to have a forged 4130 Eagle crank. How do I verify what the crank is? Since I've got the motor out, It will be easy to check.

In all honesty, I don't see where 500lbs could be removed without a TON of money being spent. There's nothing in the trunk, no spare or jack, no carpet or padding. There's nothing but essentials in the interior, carpet, stock seats manual everything nothing power, basic stereo nothing fancy. Under the hood pretty much everything is aluminum that can be aluminum. I guess I could put a manual steering box and save 10 or 15 lbs and lose some parasitic drag from the power steering pump which is probably worth a couple HP/TQ and get an aluminum water pump (which is planned) and lose another 10 lbs. The car has a stock GM starter on it that weighs a ton, but it's going back on until I need a starter and I'll replace it with a mini starter probably worth 5lbs? Other than going to fiberglass body panels, I don't see what could be removed to lose weight. I see maybe 100 lbs weight loss being simple, before it gets down to light weight seats and a stripped interior with fiberglass panels and lexan glass. I'd be down with the lexan glass but that stuff is expensive and not DOT legal, and I want to keep the full interior. I'd consider removing the rear seats... They're such a tight fit that I doubt anyone but a small child could sit back there comfortably anyway.

I already thought about the carb being a bit big, but I looked at the Holley website and they have a chart for power level, max RPM, and cubic inches... And the carb I have is in the high end range of what they recommend.