chad89ta

i went to the track saturday night and ran a best et of 8.2 at 90 mph i was hoping for a lot better,the mods 650 holley dp jetted 71 84 performer rpm intake dart iron eagle heads 215 cc intake runner and 64 cc combustion chambers with trw flat tops comp cams extrem 274 230 236 @.50 488 490 lift full 1.6 roller rockers hooker super comps headers 1 3/4 full leanth true duels three inch with h pipe, msd pro billet dis hei. msd 6al with blaster 2 coil motor is a 355ci does this sound right i thought i would be in the mid 7 range wtf

Blackroc86

That does sound a bit slow for your setup. What was your 60ft like? It could be possible you were spinning alot.

chad89ta

60 ft was 1.90 with street tires i no my et would have been better with the nittos or slikes but the mph seems low to me

chad89ta

also the car has the tko t-5 5 speed with 4.10 gears and the moser 9 inch

Blackroc86

Your 60ft wasn't horrible but you should have at least been in the high 7's I think.

cp87GTA

Well you asked. Your running a street cam, and carb. With race heads. A bit of a miss match in my opion. With 1.9 60 footers tells you're spinning a lot. Get those down and your ets will drop. I run 1/8 too, in modified class. Most guys with your mods run about what you are. I run 7.000 to 7.009s and only run 103+. But I have 1.42s to 1.48 short times. What gears are you running? The GTA in my sig runs 8.80s with 1.9 short times with street tires. I don't think you're doing too bad.

AlkyIROC

That's a big head for such a small carb and cam even with the 1.6 rockers.

It could be a number of different things. How much lift are the heads and springs set up for? Total ignition timing? Weight of car with driver going down the track?

chad89ta

total timming is 38 the heads have 205 160 valves duel spings 1.437 they are good for .620 lift and car stock wait is 34 to3600 lbs not sure,and im 215lbs,lol so what size cam should i be using the car pulls hard till rev limeter kicks in, i sift at 6500 rpms

87_TA

90MPH is pretty good!!!!
You are making good hp just not using it. I would say that 90 MPH should get you 114 MPH in the 1/4 mile. And that enough MPH to get high 11's - Now work on the driving.
If you could pull a high 1.7 60 that should get you real real close.
Beside if you pick up that 60 ft your MPH will get a little better assuming you are bogging now.

chad89ta

87 ta,do you think the heads are to big,if so what cam should i be using, thanks 4 the info

87_TA

Well I agree that the carb may be on the small side, and I think you would benifit from a victor jr or comparable single plane intake as well.
With those big heads on a 350 port velocity is out the window and thats all of your low end torque. So take advantage of the High RPM HP ..
What is the LSA on your cam? That duration is @ .050 right?
(nevermind the dur. just saw it.) HYD FLAT TAPPET?

Either way you have a good runner... Dont sweat the time , MPH reflect HP and you are making it.
90 mph can get you a 7.7 1/8 mile or better.

chad89ta

yes hyd flat tappet,yeah im thinking about getting the victor jr,what cam would you recommend,or would you just leave it as is and run 100 shot of juice

unknown_host

iTrader: (1)

I think those heads are too big for the displacement and camshaft you are running. I go 7.9's with smaller (vortec heads) on worse (2.0) 60 foot times with the same camshaft (XE274) and displacement.

87_TA

Well you could leave it as is..
But if you decide you want to get more from the combo I would get something with a tighter LSA - Maybe like a 106 or something to take advantage of the exhaust scavaging and go with a solid to run the rpm the heads will want to. Also get the lift up in the .500s to let the heads flow at their near their peak.
But I would not run out and buy those things either - Like I said you have a good runner now, Now you just have to take advantage of that power. But if you want more, ^ there it is.

AlkyIROC

Although the springs can take that much lift, are the heads set up for it? What's the maximum lift of the head? If the valve guide isn't machined down enough, the bottom of the spring retainer can hit the top of the guide.

According to the Comp Cam catalog that camshaft operates in the 1800-6000 range. Since you're shifting at 6500, a step up to the next one XE284 would be better since it builds power to 6500 rpm.

You should have a minimum of a 750DP carb. An 800 or 850 would be better. You have big heads, valves and exhaust but a tiny carb. With those 2.05 intake valves you should have an even bigger camshaft (much more duration). How much compression ratio is the engine and what grade of fuel are you using?

The Performer rpm intake isn't bad especially for a street driven vehicle since the dual plane design builds low end torque but a Victor Jr would really help on the top end.

unknown_host

iTrader: (1)

Agreed, a compression bump couldnt hurt either.

chad89ta

the heads are good for .620 lift thats what it says on dart web site im running trw flat top 10.5 to1 on 93 pump gas

chad89ta

what do you mean by lsaok i got it the cam is 110

87_TA

Well a tighter LSA give you overlap of the ex and in valves meaning they are open the same time for a given duration.
What that does is - The exhaust valve will still be closing while the intake is starting to open. What that does is the charge of exhaust flowing out of the chambers creates a vacuum in the cylinder helping to pull in the intake charge.
I personally think you do not need much more duration (some will not hurt) But you have plenty now..
The LSA and the lift will now help you. only down fall of the LSA being LUMPETY LUMP and low idle vacuum..
But I am living proof you dont need that much for power brakes.
My camaro used to idle with less than 5 inches and the brakes still worked pretty well, worse case senario you need a canister.
Welll bed time here, 4 am comes too quick. yawn

chad89ta

what are the specs on the comp cam ex 284, thanks guys you have been a big help:hail:

muggsyjack

We are running a best of 8.11 @ 85.5 MPH w/1.85 60' times. This is with a 305.

With your 355 your MPH is up there, you are making power. I would agree on potential mismatch restricting you a little. The biggest element is 60' times. We saw a best of 8.26 with 60' at 1.90. When we got 60' down to 1.85, ET dropped to 8.11. .05 off 60' dropped .15 off ET for 1/8th mile.

Our restriction at present is stall speed. Driver (son) sees 3,200 RPM at launch. This is too low for puny 305 minimal torque output. Last Saturday, he made 10 runs w/60' all in 1.845 to 1.855 range. Debating whether to increase stall or replace single plane manifold. Removing 1 inch open spacer dropped 60' time by .05.

chad89ta

what rearend are you guys using,cant be the stock 10 bolt,best ets ive heard for a 305,wow

muggsyjack

10 bolt w/4.10 gears and support cover. 28 X 10.5 X 15 M/T slicks.

chad89ta

stock axles,i broke three of the stock axles and a ring gear,so i finally said f**k it and spent 2000 on a moser nine inch

unknown_host

iTrader: (1)

I am running the stock 7.5". It has a zexel torsion posi and 28 spline axles. I will be running it on slicks and nitrous this year, 7.9's was off the bottle with no slicks. I will let you guys know when it pops .

muggsyjack

We got a 1992 rear. Have not an axle break yet. Originally had a truck posi. It started slipping so I installed a $99 take off Zexel unit. Put rear support cover when changed slicks. So far everything is working fine. 60+ passes. When I installed 4.10 gears, I welded axle tubes to center section.

The 305 probably does not have enough torque to hurt rear with automatic transmission. After we break into 7's will install nitrous setup. Next stop after that will likely be a 9 inch.

87_TA

Well I'm running an Auto so its a little easier on parts but...
stock 10 bolt , zexel torsion, 3.73's.
Best 60 ft 1.54. Just switched to 4200 stall well see if I cant pull a 1.4 outa the stocker.

chad89ta

DAMN I MUST HAVE HAD BAD LUCK WITH MINE. THE FIRST ONE I BROKE WAS THE FACTORY 28 SPLINE THEN THE OTHER TOO WHERE THE 26 SPLINE,I NO THE 26 SPLINE ARE WEAKER BUT THEY WERE FREE,AS FOR THE MOSER A LOT OF CASH,BUT ITS BEEN WELL WORTH IT FOR ME AT LEAST.LOL

87_TA

Its kinda worth it to get 28 spline axles only because SLP sells take out Torsions for only $90.00 dollars and so does Thunder racing I think.
Its the total option if you bust one.

cp87GTA

There is a guy running a s10 at my local track. Has a built 383 sbc, just later part of the season started having rearend problems, but he is now running high 650s to low 660s on 12 Hoosiers. He has the stock 7.5 WITHOUT a girdle. I talked with him the last race of the season, and he said he had no troubles at all till he got the hp. to run 680s. I think they are stronger than people say, just depends on how they are setup. When I bought my GTA it had a set of richman 373 gears in it, and a lot of noise. I took it out and installed a set of 4.10s. When I pulled it, had so much clearance in it, if I were to try and use it . It would have destroyed. I am a firm believer in a good torque coverter too. chad89ta,, is this car a street or a race car? If you go much bigger on the cam you WILL need a converter to go with. I had a torco converter built for my race car, and we broke the engine in on the street. Worked real well, I also bought a 2400 from anouther company for my GTA, and it was JUNK! It does make a differance. I'm thinking on useing a comp 305h in the GTA this season with a new converter of course.

chad89ta

my car has the tko t-5 speed,