If you were building a motor...

[kornball426]

Here's what I'm wondering... I'm thinking about building a SBC for my car that I want to turn into a stockcar. I realize that this is more drag race oriented board, but I just thought I'd ask. So I have two choices, imagine one 355 with stock double hump heads other than 2.02/1.60 valves, with a Q-jet on a stock iron manifold. And the other 355 with stock Vortec heads 2.02/1.60's, with a edlebrock performer intake but limited to a 500cfm holley 2bbl.

All other things being equal, compression, cam, stroke/bore, etc. Which do you think would be the faster motor? The one with the oldschool heads and intake, but with the carb to feed it... Or the one with the better heads and intake, but a carb that chokes it? Bearing in mind no porting being done to the heads or intakes.

 

[billyjack]

First questions I can think of to add a bit of info:
How big are the tracks you plan on running?
Dirt or Asphalt?
How tight do you expect to be turning the engine?
Is there any kind of camshaft rule?
How are the turns, tight or sweeping?
What type of fuel are you running?
I would assume this is some kind of "equalizer" in the rulebook. Do you know what combination most of the competitors are running now? I'm not much of a stock car guy, since most of my experience has been in sprint cars (see avatar), but there are a few folks here who participate in circle tracks, so you very well may see a few guys jump into the thread.

Bill

 

[kornball426]

I was trying to take the variables out of it. :lol: And I'm an absolute beginner at understanding how circle track works, I've never done it... Except in a go kart, it just looks like a lot of fun and I want to get in on it but I don't know which track to build the car for. So I figure the easy way to pick is looking for the one with stronger running engines. :lol:

Track one is a dirt 1/2 mile and has two tight-ish turns, and two long sweeping sides. Allows 10.5:1 comp, box stock Holley 4412 carb only, on any stock manifold or unmodified Edlebrock Performer. Since you're not limited to iron stock manifolds, that means you can run Vortec heads as I would think not only would modifying an oldschool iron manifold to fit on Vortecs wouldn't work very good, I'm also guessing that would be an illegal modification of the manifold.

The other is a dirt 5/8th mile has one straight, two somewhat tight and banked turns, and one long sweeping side. They don't say you can't mod the carb, and you're allowed to use a 4bbl as long as it's an OEM style carb... And you must use an iron manifold. And they don't have a compression limit posted in their rules in their drivers forms and what not.

For both tracks: On the camshaft any flat tappet stock diameter lifters solid or hydraulic but the car must pull minimum 14 inches vacuum at 1,000 rpm. Fuel is pump gas, or any so called "commercially available race gas", I dunno what that means specifically that's one of those vague things. Both allow headers (no tri-y's), with 2.5inch exhaust must have mufflers, don't know about X or H pipes not stated in the rules. Both have a weight minimum of 3200lbs with driver. I don't know about the revs, there's no limit posted or anything... I have no idea, 6000-6500 maybe? Forged I beam rods, hyper alloy pistons, and a cast crank should be able to survive that for a season I would think no?

 

[billyjack]

OK, so you're a rookie. We all started somewhere. It's not time to build a car yet.
First thing is to find a crew that needs some help. Get a pit pass and circulate. Look for a car that appears to have decent craftsmanship and a driver who is smooth. They may be a middle of the pack car but that's OK. Once again, look for a smooth driver with a mature-acting crew, who may not have the best equipment, but seems to be getting all he/she can out of what they have, not tearing things up and acting in a reasonably professional manner. After the feature, or during an idle time in the program when they're not doing any work, introduce yourself and ask if they could use some additional help. Don't come around asking questions when they're feverishly thrashing on the car to make the feature call, but wait for an idle time in the show. If accepted, show up at the shop on prep night to get familiar with the car. Eventually, start asking some questions on setup. If you're lucky, you'll find someone who has a grasp as to the theory of chassis setup as opposed to just trial and error. On dirt as well as asphalt, intelligent chassis setup and good guesswork, since the track is in a constant state of change all night long, will beat an all motor-no chassis car hands down. Spend this season learning and keep notes. Watch for good buys on parts or tires and start accumulating pieces for your own car. Spend the off-season building your own car and you'll be way ahead in your learning curve next season.
I know this probably isn't what you wanted to hear, but after 25 years in the pits and shop wrenching on a sprint car, it's the best advice I can give.

Bill

 

[kornball426]

Well yeah not what I wanted to hear but don't take that the wrong way... :lol: It makes sense and I would do that because it makes sense to learn from the bottom just like anything else. Just like you don't become a rock star just because you bought a guitar, so why would you jump straight to building your own car when you've never even been on the track? But the thing is I kind of can't right now, I wouldn't be much help to a team I got hurt in an accident and I can't work for like a year I gotta do rehab and stuff so I'd just be in the way. And the main reason I want to do this (other than it looks fun) is, I've got a car that's solid but needs a lot of work if I want to put it back on the road and I've got some money and I've got some fab skills. So I wanted to build the car while I'm hurt for something to fill my time then next year actually go racing with it. Plus when I actually go back to work I'll never get time to work on any of the projects I want to do. Sorry I don't mean to sound ungrateful for the advice it seems like sound advice, but I doubt they want a guy that can't stand up for more than a couple minutes at a time because he's got a bum leg.

But anyway just for sh*ts and giggles I still want an opinion. Gen 1 SBC heads, iron intake, Q-jet... or Vortec heads, edlebrock intake, 500cfm 2bbl. All other things being equal what do you think would put out a bigger number and wider power band you think? I've been thinking about it endlessly.

 

[canadiantbone]

Vortec with the eldy intake & 2 barrel carb . remebering that a 2 barrel will give you more torque & the vortecs do breathe well for what they are . IMO .

 

[SScamino]

vortecs are much more superior my friend

 

[username]

Theres nothing like jumping into something head-on but like Bill said your better off becoming familar with some of the ins and outs before building a car. You mentioned being in an accident recently and going through rehab,you do realize that dirt track racing is a rough sport especially entry class cars,( I raced a hogg class for a couple years in NW Fla) and why I say more so with a entry level cars is because people like me started in with entry level experience.Did I have fun? HELL YES 😀,Was I a front runner? NOT A CHANCE The only way I wasnt sucking hind tit was if somebody DNF. :wink:. But think twice about racing if your sore or have a hurt back because you will get banged around quite a bit,think 3000lb bumper cars. I say if your up to it go for it.

 

[kornball426]

username- Yeah I've been banged up in many an accident from cars and dirtbikes, right now I've got a broken leg that had to be surgically reconstructed and haven't walked since January 23 and won't be for a while. :? And I've broken my back, my foot, a couple of fingers and toes, and a couple of ribs. But what's the point in keeping going on living if you let pain keep you from enjoying anything in life, and let fear of getting hurt stop you from getting out there. I'm only 22 I can't give up on living yet. :lol: That said, if I go through with this which I want to I'm gonna go all out on the cage, and get a nice supportive seat and harnesses, neck supports... Every safety feature I can. And hey, it's GOT to be safer than my former hobbies of dirtbiking and jumping old cars over the railroad tracks.

Post--> I read somewhere that 500cfm from a 2bbl is deceiving because they're rated at 3.0hg as opposed to 1.5hg for a 4bbl, I don't understand how they came up with the system or how it works exactly, I read an explanation once but it still doesn't fully make sense to me. But what I read is that in 4 barrel terms (convert 3.0hg to 1.5hg=2bbl CFM / 1.414) a 500cfm 2bbl is actually 353cfm, or roughly little less than half of what a Q-jet flows (rated I dunno real world). Though the system dates back to the 20's apparently, and there's no way motors back then could make near the vacuum and RPM of a SBC especially once it's got decent compression.

Though if that's true you think the better flow of the heads makes up for an over 50% restriction compared to a Q-jet? GM advertises that vortecs will make 20-40 hp more than old school heads which I'm sure is true if all things were equal other than the heads. But it seems like maybe that might get negated by having a tiny carb on there especially on a motor where low end is less of a priority than on the street and mid range and top end become more important.

But I saw a well prepped vortec motor in a magazine online that dynoed over 450hp with a 500cfm 2bbl so something is weird that I'm not getting.

I dunno I'm just basically thinking out loud... I've confused myself help me.

( I should change the name of this thread to the, "I state a bunch of bullshit thread" )

 

[AlanB]

If I understand you right, one track near you runs the OEM head rules, and the other runs the Vortec head rules, and you are trying to decide which one to run based on which one makes more horsepower?

If it were me I wouldn't make my decision base on HP. Instead, focus on which track offers the best environment for beginner. Smooth surface, supportive tech staff, friendly racers.....

Go visit the pits at both tracks and make friends. Just flat out tell people what your are trying to do and ask for their opinion on which track or engine combo is better.

I agree with others that the Vortec setup should make more power, but in either case the top runners are running professionally built motors with all the tricks. OEM guys are running select castings, professionally prepped to flow way more than stock but still pass tech. Vortec guys are probably running high dollar carbs made to look box stock. Vacuum rules are easy to tech, but favor guys who can test on a dyno or have the money to buy from a pro.

My local track, New Egypt Speedway, has a 14" vacuum rule, and lots of guys run Rhoades? Lifters to get away with a bigger cam.

If it were me, I would focus on handling over power. Things like bushing hardness, control arms, ball joint height, alignment, springs, shocks, wheel offset, brake bias, gearing, etc, will get you a lot further on a tight budget than HP.

Just 2 cents. Hope it helps.