I want to know if anyone is running a good rectangular port head combo in a heavy chevelle ?

I do not want to start the rect. vs oval port debate just the best combo we can use with this rect. heads with a 3.76 stroke IN OUR HEAVY CARS.

Fast depends what town ya live !!
I have a couple of combo's.
It would be best to post how fast you want to go and what parts you have,car weight etc converter.

Her is my combo ,

427 tall deck .030 over ,6.535 rods balanced TRW pistons 2239F - .125 flycut = 31.3cc
10.2 compression
990 rectangular port heads with manley race flow valves 2.250 in. and 1.880 ex.
solid duration at .015 282-290 Comp Cam
@ .050 244/252
590in/598ex.lift
3500 converter ,th350 ,4.56 rearend the car is a little modified to 31 x 16.5 rear street M/T sportman tires ,all my runs down the track has been with no headers,
RPM air gap with Holley 850
and now with 1 3/4 headers with 3" ex.,no test with headers with the heades I hope to hit a 12.9 -12.8 :D ,my goal 11:7 -11:9 :cool:

What are you et's rcatala? And how is it on the street?

Depends on what you consider fast? I scaled my car yesterday at the track and with me in the seat and 3/4 tank of gas it weighed exactly 3,760lbs. I just posted some new best ET's in this thread (http://www.chevelles.com/forum/ultimatebb.php/topic/4/22957.html). That's a 10.37:1 460ci engine with TH-400, 4.10 gears, running through mufflers and tail pipes.

rcatala, with that combo and running that slow you have something wrong, with that 60' time and only a 13.18 your car is laying down on the second half of the track
headers on a bbc or a sbc usually cut .5 off in a 1/4 mile, more if the engine is cammed stout, which yours is on the verge of.
what fuel system and distributor are you running?

Crane HI-6 ignition the distributor is lock and timing at 42 degrees ,I did try it at 36 but it did get better with more timing even try it at 44 but no improvement and put it back in 42 ,Carter 4889 120 gph at 6.5 regulated psi stock fuel line with.

I leave the stage at 2800 ,shift at 6500 RPMs to 2nd & 3er,no way I can lauch at more RPMs the car rolls ,I got a th400 with transbrake just need new kit ,looking foward to try it ,just got the TH350 rebuilt

what car is this? year and make and original engine size? your link is not working.

Sorry ,it is a 1971 GMC SPRINT (same as elcamino)original 6 CYL.car

and would the stock fuel line and pickup in the tank be 5/16 or 3/8? i would think in a 6 cyl it would be 5/16 and that might be part of the problem. do you have a fuel pressure guage on it so you can see what its doing at half track and beyond ?

and if this is a fuel problem the headers will make it worse, it will be needing even more fuel with them because of the horsepower gain

what mechanic427 said. if that was originally a 6 it has a 5/16" fuel line from the tank to pump. Also, the pickup tube inside the tank is going to be 5/16". This stuff needs to be replaced immediately. your slow top end is the the tip-off, you're probably lucky you still have 8 pistons. You're in a excellent position to end up with only seven and one-half pistons. bummer when that happens.

Tom

Javier, Tom means losing a piston by going too lean( due to lack of fuel) and literally melting or detonating one.

Hey, the good news, if you are running a 5/16" line, the next upgrade to 3/8" or even 1/2" will be very noticeable and not much $$. A bit of a hassle getting the pickup right, but no big deal.

MECHCANIC427 ,how I upgrade the fuel 5/16 line inside the tank ,any kit or thrick ?Thanks for the advise guys,I am not even taking the car for a little cruise today not until this is fix graemlins/clonk.gif

I remember the last time at the track a friend tell me that my car sound like if it was hitting the rpm limiter at half of the track down ,I though it was the RPM limiter so I set it at 7000 but I did not find him to ask againg ,but this is got to be the problem ,I am new at the track and with a helmet I am a little lost

I am running the Dart Pro1 310cc Rectangular Port Heads on my 3700# chevelle. 10.30s @ 129

there is a couple of ways to do this, you can replace the pickup with one out of a big v8 elcamino/sprint (e/s for short). or you take yours out and a competent shop can remove the 5/16 line and solder in a 3/8s or my choice (since you in there anyway) a 1/2 line. if you go 1/2 besure to put a filter on it right off the tank since i don't think anyone makes a 1/2 sock/screen to go on the pickup. 1/2 will cover you if you decide to up the hp with bigger cam or blower or nitrous later on, no since doing it twice.
e/s fuel lines are available a lot of places even some in 1/2 stainless steel i believe, but getting them to puerto rico in one piece and not all bent out of shape i don't know about, or you buy tubing and bend it yourself or go -8 or -10braided line which will have to be replaced every so often at great expense also. and the car is safe on your cruise today you will only notice it on a sustained hard use. 5/16 will keep up with about 200hp but not any higher.

Just go to a half inch line if your going to change it. It cant hurnt anything and could only benifit you later on down the line if you start making alot of power.

I am going to take the fuel tank out tomorrow and start to do this ,I will install the 1/2" line .
What good flowing fuel filter it should be installed right of the tank ? How low in e/t this combo should be running ?

Sorry for all the questions asked:

This combo has been build thanks to TEAM CHEVELLE MEMBERS recomendations and I am proud of it but like everyone in drag racing who don't want to be faster? :D .

Javier, the 1/2" aluminum line can be easily bent by hand and isn't very $$. I don't know about durability long run, but if you are careful to use the rubber insulated hold downs and keep it from rubbing anywhere, you should be fine.

Man, I pray you're in for a BIG BIG surprise next time you race it!

What sort of fuel pump are you using?

1970 LS-6 Chevelle

.065 over LS-6. Dynoed 496 HP/ 532lbs with stock cam, intake, and exhaust manifolds.The carb was a Holley 930 Carb Shop from the dyno operator since the stock 4557 780cfm carb was burping and farting to 3500 rpm. With the burping and farting it made 481/521.

The car weighs 3869 with me. At the Pure Stock Drag last Sept we went 12.82 with the Firestone Wide Oval tires an a 3.73 gear. Best 60ft was a 2.11. Should of gotten into the 12.70's but didn't do to my driver error. The results are in this months MCE

Your combination should have no problem making it in the 11's as stated. The rectangular port heads are good. I know we have people that state otherwise. Like any engine, it is a combination of parts that make the thing work.

Jim

I think you'r timing would be better served between 35-38 degrees. The only time I've seen 40+ degrees are the guys whom run aluminum heads. Are you sure the distributor is right where it should be?

WOW Jim :eek: ,I am using a Carter #4889 120gph ,7.5 -8 psi fuel pump ,I did post a NEW topic :CARTER 120GPH FUEL PUMP AND 1/2" PICKUP LINE, I got a few MORE ,????????,SORRY redface.gif

Gene Sir , really think the car can e/t lower than 12.8 e/t ? Mechacanic427 noticed a problem from half track down and tell me to go with the 1/2 " pickup line. only the pickup with 1/2" ?

My real goal is 11.90 if this is going to e/t lower than 12.8 ,I am going to do this tonight .

Jim I am using a tall deck with .400 longer rods ,I did some reading and the longer rods can make you run the ignition with more advance ,I did a search in TEAM CAMARO ,that is wy I try more advance and the car went faster ,My freinds and I are going next time to the track with a BATMAN belt full of jets to try some tunning in the track, we set this allways at home and run the car 2hours to get there and only set the timing at the track

Jim,nice numbers with impressive performance graemlins/thumbsup.gif
You Pure Stocks guys always amaze me :cool:
Going to NJ/Raceway park this Saturday to watch pure stock and FAST class run..

Originally posted by rcatala:
My freinds and I are going next time to the track with a BATMAN belt full of jets to try some tunning in the track :D Now that was funny! :D

Javier, All the rat motors with a domed piston will respond to a lot of timing. If it works best with 40 degrees of timing don't worry about it if you have good gas. You might also check to see how close the carburetor is in relation to the hood. I once put a hood scoop on a Camaro and gained 3 1/2 MPH. The carb. needs at least 2" of clearance between it's top and the bottom of the hood. All the square port rat motors like a lot of cam. The old ZL-1 cam picked up my 396-375 eight MPH which i think was about 80 H.P.

Originally posted by mechcanic427:
5/16 will keep up with about 200hp but not any higher. I've got about 440hp and the 5/16" fuel line works just dandy. Does it really make any since to use 1/2" fuel line when the fuel is gonna get all backed up at 2 little .110" diameter needle and seats? I agree though, that big block should be runnin low 11's or 10's so it does sound like something is wrong with fuel or ignition, I don't think its just the fact that it's 5/16" line but maybe a clogged up filter or a horrendous kink.

Sorry doble post

19NOVA72,What is your complete fuel system set up ?
Do you run the stock pump ?
Because I run a 120gph pump and that is more than stock pump but the volume will stay the same if the line is not change.
The thing is that I had problems with out any indication that can noticed,and with the helmet make it even worst but the people outside did notice they tell me "like if the car is hitting the limiter but lower in sound from half track down" that what they say,I run thru mufflers not a thing that can be hear with a helmet .
this is not a big project,but now I am late for doing this and I think I can not do a test this saturday :(

Javier, if you really want to go 11.90's, put the headers on! Your choking that motor. As far as the rect port heads go, I can comment. I had a set of 990's on my +.060" 427. It ran 12.20's. I switched to GMPP roval aluminum with a 290 cc intake runner and went 11.988. Well it took 75 lbs off the nose of the car, and that run was made without the 1.25" sway bar on and it ain't light either! Oh ya, I had the entire exhaust system off. Open headers without extentions. No problem hearing it thru the helmet. So I took a total of 143 lbs off which accounted for at least 1/10th. I'm putting the rect ports back on that motor as we speak. Do the fuel line. If nothing else, you're eliminating that factor. Once you get your car sorted out, I bet your 11.70's. Headers dude!

Does anybody know how much horsepower a BB Chevy has to make before the stock fuel system runs out and performance is effected? Lots of variables but just an off the cuff estimation?

Jim

Thanks for the kodo's guys! Trying to make the car a contender! We'll get their with more test and tune.

Jim,with your MPH,thats an easy 11 second car,but with the bias ply tires,it'll never be able to 60 ft. hard enough (low 1.7X's) to get there.
It's very impressive no matter what,a 4000 lb car with manifolds and bias plys running those numbers (12.7X) just amaze me graemlins/thumbsup.gif
I would have to try a few runs with some DOT slicks,just to know what it can really do ;)
IMHO and experience,your factory fuel system is supporting your combo nicely.I'd say once you get over the honest 525+ HP at the crank,you'll at least need to upgrade to a 120 GPH mechanical pump.Again,your MPH indicates your fuel system is doing its job.

I used to race with a guy with an all steel 70 that ran the old 9.80 Pro Gas.

CHEVYWIDOW ,the headers are in but everyone said I still got the line problem to fix before the next race at the track and the more HP with headers the problem will get worst .
WOW 11.7 ,OR YOU MEAN 12.7 ? COME ON ,REALLY :eek: :D ,WE SURE ARE GOING TO NEED THE BATMAN BELT ,full of everything jets light.... :D ,I can not make it this weekend to the track alot of rain here and got a lot of things to do today .MAN I REALLY WANT TO GO TO RACE