was wondering if someone could run the numbers for me on some combos and see what kinda numbers ill get. im not entirely sure whats needed but i assume heads, cam and intake are a big part. ill also be running 3.73 gears if u need that. the first cam is a custom ground cam that was designed for a daily driven engine to get decent mpg and still have enough power for the weekends. and the engine is a 355 and will probably have a 600cfm edelbrock carb. i appreciate any help.

head options:
76cc, 2.02", 1.60"
64cc, 2.02", 1.60" vortecs

intakes:
edelbrock performer
edelbrock vortec performer

cams:
246/241 duration at .050", .505/.515" lift, 116 lobe separation
230/230 duration at .050", .480/.480" lift, 110 lobe separation
233/241 duration at .050", .504/.525" lift, 110 lobe separation

 

what is your CR

 

CR?

 

compression ratio... and which heads are those i need them for the flow numbers

and those cams i need actual part #s or actual specs

 

as it sits now, 8.5:1 with flat top pistons. 76cc is stock heads, 882 casting i think. and the vortecs are from scoggin-dickey, pn# SD8060AKIT

 

huh well have to say this is kinda a NO BRAINER... the vortecs with the vortec intake

and the 233/240 at .050 .504/.525 probably around 430-440 FWHP

 

with the custom ground cam and the vortecs, my friends d.d. said id make 434hp at 6000 and 416ft/lbs at 3500 and id be makin no less than 350ft/lbs from 2500 and up. i just wanted to see how the stock heads compared

 

the stock heads dont compare... not even close... think 190HP... not good.

i might ad you probably arent going to like that "custom" cam for daily driving... try to keep the duration at .050 below 240... i might also add that the ramp rates necessary for a cam with 246 degrees at .050 with a LSA of 116 might be very tricky to get not to mention way more aggresive than you will like

 

ah damit, i meant to put 236/241 on the custom cam

 

okay the other problem with a very LOW overlap... or wide LSA such as 116... you will be retaining much more compression... IE the vortec heads will give you about 10:1 CR with flat top pistons and a deck height of .025... stock deck height that is you will probably find your pistons sit a bit lower...

but for planning purposes 10:1 CR with that cam i had to use DD2003 to guess at the actual numbers but a 55* IVC gives a 8.5 DCR or Dynamic compression ratio higher than you should run for the street

 

retaining compression? i know more compression = more hp, but this will be a daily driver, i need to be able to run pump gas. also more compression = more noise, and i dont want that. all the rest of that confused me

 

That custom grind looks a bit whacky to me- big duration but a wide 116* LSA. I just can't imagine how that would work well, but that's just my opinion.

Agreed the Vortecs would be a good call- much better than your 882s. Your compression ratio with flattop pistons and the Vortec 64cc chambers will be up in the high 9s.

Just watch your valve lift- stock Vortecs can't take any of those cams safely. If they're modified for increased lift I'd still go on the small end of the spectrum for the cam. Not a big fan of cams over 230* duration for a daily driver- especially not with 2.73 gears out back! If you plan to use the stock converter in your trans I wouldn't even go over 220* duration.

You look like you're almost ready to fall into the old "too big a cam" trap with the 3 choices you posted.

Your combo would be a typical candidate for the tried-and-true Comp XE268 flat tappet hydraulic (224/230* duration, 110* LSA, .465/.470" lift). It may not sound big but it's got about 20-25* more duration than most "stock" cams and a tighter LSA for some good midrange torque. It would also work well with your planned 2400 stall converter and 3.73 rear gears when you get them installed.


And lastly- please install the correct springs for whatever cam you choose AT THE PROPER INSTALLED HEIGHT RECOMMENDED. A performance cam with stock springs, the wrong springs or even the right springs at an incorrect installed height is worthless. If you get lucky it just won't make good power in the upper RPMs due to valve float. If you get unlucky you'll break parts, wipe out cam lobes, etc.

 

yeah i thought the cam was a little strange too, but i know the guy who bought it and the guy who made it knew what they were doing. its designed to have power but still keep enough vacuum and keep it streetable. the heads are modified to accept more lift (0.550), high performance z28 springs and lightweight LT4 retainers. im DEFINITELY not gunna have the stock converter. im not sure what converter to go with, anything 2500 or higher would be good with the custom cam. and i might keep the 2.73s in but they will quickly be swapped out for the 3.73s i have layin around. and im not so sure a cam under 220 duration would get me in the 12s.

 

you are right a cam with under 220 duration probably wont get you into the 12s... but then your gas mileage will suffer more... as you are already know you will need a bigger stall/numerically higher gears(3.73) or 3.42s...

it is going to be very difficult to get 12s and still have the mileage you sound like you want... so make up you mind!

 

mileage i can deal with, its streetability that i need. my mine is made up, i want a 12 second daily driver. this would be much easier with a 4th gen, but i dont really have the money to buy lsx parts. and all the 3rd gens i see are either drag cars, pos cars, or just slow cars that look nice. im goin for a street/strip car that can still turn heads in a good way.

 

Ill sell you a cam.....

.050 268/278

.660 lift

108 LSA

 

I think you'll find there are plenty of guys running around here in the 12s with the Comp XE268 cam (which is just a bit over 220* duration). It's the combo that counts, not any single part. Cam to match the combo, don't build the combo around the cam.

Your gears, converter and rear tires are going to make a big difference in the likelyhood of you reaching the 12s.

Let's assume the following: you upgrade your heads to Vortecs leaving the rest of the motor alone, top it with that 600 CFM carb, install a 2400-2500 stall converter and put 3.73s in the back with some sticky tires. What cam would match that combination? I still would say something under 230* duration. The rest of the combo is too mild- converter stall too low, 600 CFM carb a bit small for high RPM operation, compression ratio probably only around the mid 9s. All that puts limits on how much cam you can put in it before bigger cams stop helping the car go faster and start slowing it down.

And the old rule about cam choice still applies: happiness is often a cam that's a little smaller than you think you need.

 

um...thats more like a trailer queen drag cam...so no.

any idea what kind of hp and tq numbers the combination u just gave would put out? and would there be any noticeable difference between the edelbrock performer rpm air gap and the edelbrock performer intake? if so, how much?

 

you think the XE268 is a trailer queen drag cam? i run the XE274-10 on the street every day drive it to work....

if thats your opinion you really have no business looking at anything other than the stock cam

 

not the 268, thats advertised duration. im talkin about the one zones wanted to sell me. i tried to quote it but it didnt work i guess. .660" lift and 268/278 duration at .050 is WAY too damn much for a street engine.

 

you never know that cam would be pretty mean in the right setup... if you dont care about mileage

 

Yeah I got a 244* Int/Exh at .50 dur with a .510 int/exh lift on a street car its starting to see the road soon so I can tell ya how the mileage is with the 600cfm carb app.

 

Yea, i was kidding, i wanted to put it in my 408 i am building...till i found out how big it really was, think ill go 246 256 duration @.050. .600ish lift.

 

Ok I drove my car on the road approx. 90 miles today and use a 1/2 tank of gas with my setup and cam I have. This was 75% freeway driving, although for 20 mins I had stop n go traffic. Its roughly maybe max 11-12 mpg.

 

not too bad i guess...lol