Well I am new to the site and from what I have read so far this seems to be the site that has the answers, so here it goes. I have a 81 Z28 and I want to be able to destroy LS1 cars. This is what I have 3:73 gears with a posi and mosler axles, 350 turbo,3500rpm stall,3" dual exhaust with 2 chamber flowmasters,hooker supercomp 1 3/4 headers, 355 with forged crank and rods, 4 bolt block, weiseco pistons, 10.6 comp. with the small chamber dart sportsman II heads, RPM performer intake, holley 650dbl (4150) and a carburator shop hei, the cam is a UltraDyne 228in,232ex, @.050 and 465in.,485ex on a 110 center. all of the parts are out of the box stock no porting. My best run so far was with 275-50-15 cooper cobra tires I had a 1.84 60' and ran a 13.34 @ 99.7. My goal is a 12.0 in the 1/4 without power adders,NOS or Blowers and with only a 355. My plans of right now are to add a X pipe and electric fans and my opinion is I need more cam possibly a solid roller and ported heads and intake. And because I am using factory forged crank and rods (LT1) I want to stay at or below 6500 as a max RPM. Well if you need more info let me know any help would be great. And you all know the car is a heavy sled being a 81 and my one track visit was with a full 21 gal. gas tank for tracktion. I have purchased a set of Nittos since then but no track times yet.

 

Weight is a big factor too. 100 pounds is equal to a 1/10 in the full 1/4 mile.

I run a 355 in a 78. Solid roller,TFS heads,Jr Intake,Chuck Nuytten 850 carb,cast crank,rods,KB pistons. I turn is 7000 with no problems. Car runs an occasional 11.9x but a consistant 12.0x@115 with a 1.70-1.75 60ft The heads are box stock.

My car weighs 3200 and change with me in it.

My guess is your going to need more cam and carb.
Car is going to need to go on a diet possibly.

Ray

 

without putting it on the scale i would guess it has to be all of 3500 and i'm 180 so its not light but it is a nice car that I show and drive on the street, its just those pesky LS1 cars that my buds have that are currently running 12.7 @ 112 with just a full exhaust and a cam. By the way if my bud could drive it would be way faster he has a 2.0 to 2.3 60'. He is the one I have to beat.

 

Aren't the Sportsman II the iron heads? Everything I've seen, they don't flow quite as well as the Vortecs. Rather than going with a solid roller cam (would cost you over 1000 to convert and buy the new cam/lifters) I'd go with a healthy flat tappet and get a set of good, aluminum heads (like Performer RPM or AFR 195). Try to cut a little weight out of your car and you should be able to go 12.4's or so with that, 12.2's with traction.

 

I hope with a pocket port i can flow what the AFR heads do or am I wasting my money, and should I just bite the bullet and puchase AFR 195 or 210 heads the port job at a local shop would run around 500. If a flat tappet would be enough what do you think I would need for #s 245in255ex@.050 and 525in545ex sound about right with a 108 center?Any Ideas of a carb a demon 750 has good reviews. It doesnt have to idle well its just a toy. i am looking for a similar combination that someone else has taken to the next level and seen the numbers that I want to run.

 

Those AFR's flow pretty darn well, so you might have to do more than just a pocket porting to catch up to those flow numbers. Also, you will lose around 40 lbs switching to aluminum, and you can bump up your compression a little (use a thinner head gasket), which will also help power. I wouldn't go with the 210's, because for a 355 those would probably be a little overkill. That cam sounds good, but personally I would probably go with about a 112 center. It should idle fairly decently, but you might have to run a vacuum pump if you have power brakes. The Speed Demon is an awesome carb. A friend of mine has one on his '70 Mustang Mach I w/351 Cleveland, and while we've never put it on the dyno or anything, we've had a looooot better luck tuning it and getting it to run crisper with the Barry Grant than with his old mechanical Holley 750.

So if you can save up the money, I'd go with the AFR 195's, a solid flat tappet about the size you listed, and a Speed Demon 750. That should make excellent power below 6500, and should put you into the low 12's, maybe some 11.99's with really good traction.

 

Good 60' times on street tires! You get more power, you probably won't be able to do that. Those Nittos will help with that though. Good times for your set up too. I imagine less fuel weight (21g of fuel is a bit over 100 lbs) and light wheels since unsprung weight makes a bigger difference than sprung weight and the traction to take advantage of less weight you'll be getting close in a decently streetable package.

There are LS1's running low 13's stock. I'm running mid 13's w/horrible traction. I think its great that guys are having to mod their drivetrains internally that much so they are able to keep up with or out run slightly modded LS1s (most only have bolt-ons) that are totally streetable and can still knock down 25+ mpg. That cammed one running 12.7 should be faster than that. Thats bolt-on territory there. Is his car an auto or manual?

Don't get me wrong, I'm not knocking anyone. I had a 70 SS that ran a best of 12.90 until June. It could compete but was an expensive and not so dependable daily driver. I needed a car that I could drive daily, take on trips, get good milage, and be dependable so I got a 00 SS. I think its great the LS1 has become the engine to beat. It says a lot for it.

 

that car is a M6 and he is still learning to drive it his best mph so far has been 116 and his best time was a 12.7 with a 2.2 60' stock it went 13.3 108 they are fast and still get good mpg. i mean my car sounds nasty campared to his be he will smoke me thats why i'm posting its kind of a fun rivalry the bad part is I did all the work to his car for him, so I helped him beat me. so now i need advice how to smoke his without power adders. and without breaking the bank.

 

Bolt ons..under drive pulleys, they'll help a bit. I ran an electric fan for a while, never got any track time, but the thing revved much faster. Could do the electric H2O pump or get a kit that uses a motor to run your stock pump. Rig up some sort of ram air. Insulate your fuel lines from heat. Sometimes carb spacers help, but its iffy. If you have a stock fuel pump, get a performance model. If you're running stock sized fuel lines, go a size larger.

Internal...with your times with that sized cam, those heads seem to be flowing decent. A larger cam would help, and you could try a 750 CFM carb. If you can do the pocket porting yourself, that definately wouldn't hurt. Windage tray and crank scraper.

As stated before less weight. He's already pushing more weight than you. Get you a light wheel and tire combo if you don't already, relocate the battery to the trunk. Remove your front sway bar for a harder launch and less weight. Take out your front wheel wells. Aluminum drive shaft. Like I said, less fuel. 100 extra lbs is a lot of weight to be hauling down the track. You'll pick up about .10 from that alone. Unless you lose traction.

Ricer mods...50 HP sticker and a big wing! A little comic relief.


The M6 is difficult to launch. Once your friend gets it down, he should run low to mid-low 12's. Just a heads up for the future.

Competition is good. I seem to get guys with BB and geared cars wanting to run when I take the SS to the track. Just remind your friend that w/out your help he'd still be stock. lol

 

If you want quick HP at a low cost, slap on a Nitrous kit.A 100-150 shot should knock off close to second.

For my car a 125 plate knocked off just over 1 sec in the qtr. Yes thats on the stock crank,rods and hyper slugs. Your bottom end will handle it NO problem.

 

Well thanks for the advice, i have a perf. fuel pump but stock lines so that is a cheap mod, I have a windage tray and crank scraper, I would like to get a 12.99 with just fine tuning with fans,xpipes and such and then start changing cams and doing port jobs. I still want to get a 12.0 without spaying it and then have that as a backup for a low 11 if need be.

 

I don't know how accurate the test was but one of the Car Rags just did a test on Flex fans VS electics fans. The car picked up as much as 22 crank HP going to an electric fan and an average of 18 Hp from like 2000 to 6000.

I guarantee you will pick up quite a bit of ET if when you go to the track you run the car open headers.My car picks up almost 3 tenths going from a mandrel bent 2 1/2 " with 2 chamber flows to open headers.

Im sure an electric water pump is good for a few ponies too but then you have to look at the fact that it draws more from the charging system. May be a null point.

Good luck in your quest for speed....... it cost money.... so how fast do you wanna go :-).

 

I don't know about an '81 Camaro, but my car's hood weighs close to 75 pounds, where as a fiberglass hood weighs more like 20. Aluminum heads are worth a good 20 lbs each compared to iron. Would you be ok with going to steeper gears? Also, I may be incorrect here, but with a 3500 rpm stall converter, it sounds like you could maybe take advantage of a little larger cam. I chose my cam to match a 3500 rpm converter, and it's a 230/236 (I know, that's not much difference). It sounds like you have a good setup, though, so you may be better off just trying to subtract some weight.

 

your right that hood is heavy I remember putting it on after we painted it. I plan on going to a glass hood as it is now the wing nut on the aircleaner hits the hood slightly when the engine tourqes. so a 4 or 6 in cowel hood maybe in order. I agree with the cam advice it needs more and could take a bit more gear but it already screams on the road 3200 at 60mph. hey i figure the new LS1 cars a trapping over 100mph stock with 2:73 gears and ET low 13's in the M4 cars. I really dont know where else to pull weight without gutting the car it already has aluminium wheels. and no AC. I could pull the front sway bar. any other suggestions that are easy to do.

 

Consider going to a solid flat cam. Comp Cams has a new series of solids that tested to within a few hp of a solid roller in a Car Craft test I read a couple years ago, but at much less cost. The solid flat was the new design, the solid roller was an older "Street Roller" design. Both had around 240* duration. Hp for the flat solid was around 470. For a flat piston 355 w/Afr 190's, that was excellent power.

A solid flat with 240* duration has about the same idle and low speed torque as a flat hydraulic with 230* or so, but much better high rpm power. In fact, the flat solid beat a hydraulic roller at making top end horsepower cause the hyd roller would start to float due to the weight of the hyd roller lifters. Hydraulic roller hp dropped like a rock above 6,000 until they installed a monster spring on it that wasn't recommended cause it would kill the roller in street use. The hyd roller did make 30 more peak hp before it started to float.

Don't expect huge weight savings if you go to a bolt on glass hood. I think the 2" glass cowl I replaced my stock hood with saved about 15-20#'s; I was seriously disappointed. Pin on would save more, but are a hassle. These cars aren't light. I threw out a/c, heater (including everything under the dash & the guts of the heater control & everything on firewall) the few emissions it came with and it still weighed 3,400 on a certified scale w/half a tank. This was before I put the glass hood on. I know the RS nose adds weight, but geez what a porker.