Alright guys heres my problem. I just built a 408 with afr 210 heads, complete forged bottom end, doug herbert roller cam 246 253 duration, lift 585 600, 1.65 harland sharp roller rockers, 10.5 to 1 compression. Holley 850 DP and vic jr intake. I took it to the track last weekend and onlt ran a 13.1 at 104mph. my 60 ft was 1.9 which i dont think was to bad for street tires. I also have 4.10 gears. When i was doing research on the heads it seemed like most guys with simular motor setups where runnin low 11s or high 10s and making 500 plus horse power. Why is my car so slow. How come I am not making numbers close to other people. The clutch wasnt slipping or anything like that. My car also only weights 3300 with me. Does anyone have any clue why my times might have been so slow?

 

where are you located,
how big is your exhuast,
hedders, or manifolds,
is your fuel tuned right-getting enough of it?
is there a DYNO nearby?
timing,
and possibly gasket leaks

 

Like you said, it is a new motor, probably your first time at the track. (Please dont take this offensively) It is probably just driver. More practice with your new setup and you should pick up better times.

 

this could be true- but i dont know about 2 seconds worth unless your spinnin the tires the whole way down the track...

 

it was at pittsburg raceway . I dont have the best exhaust but i do have 1 5/8 headers into 2.5 true duels. the car was actually runnin a litlle rich but wasnt to bad. not rich enough to foul out the plugs or anything. There is a dyno nearby and i actually went to take my car to the dyno the week before but the output shaft seal on the tranny ripped no more than a couple of miles from my house and i didnt make it to the dyno. It was my first time to the track, but i really didnt spin all that much. i mean i did spin but i wasnt all over the place like my buddy. I am sure my driving did have alittle to do with but like indirocz28 said not a good 2 seconds or so.

 

with the 408 i'd say that you should upgrade to a larger diameter exhaust - the 2.5 might be a bit restrictive..

 

If you upgrade your exhaust and go duals again, make sure to put an H or X pipe in there. You could always install some cut-outs and see just how much it's holding you back.

Judging by your 60' time, it wouldnt have been 2 seconds worth of loss due to traction problems lol. Nice 60' for your first time out by the way I bet my suspension wont be able to net me a 60' like that on a good day lol.

 

Sorry to hear that. 1.9 60 fts. I was doing that with my 355 in my iroc with stock TPI. I would say the 1 5/8 headers are a little restrictive. Posibbly look into long tube headers. Does the car bog off the line? I would maybe throw some more timming at it. I would highly recomend dyno tunning.

 

Initial timing, total timing, jetting? There could be any number of reasons for low HP. My old 383 (specs still on web site) ran high 11's at 117 mph with similar specs but a flat tappet cam. I was also using slicks and getting 1.7x 60' times which really helped.

 

Make sure your new motor is actually healthy before ya start tearing into everything.

Start with a compression test.
Then test with a manifold vacuum guage while idleing and then reving the motor to 4000rpm. A bad valvespring will cause a fluctuating guage.

 

Is it just me or does that carb seam a little to big.

 

I ran an 850DP on my old 383 and was producing between 500-550 hp.

My current engine has two 850's.

 

Ok. I was just think an 850 DP is a big carb for a small block.

 

im not quite sure what the timing is at now before i took it back to the guy that built the motor to get it tuned i had it set right around 10 intial and i believe it was right around 35 total. the guy that tuned said he played with the timing a little so i dont know what it is set at. he never said and i never checked. Jetting i have no clue again the guy that tuned did all that and didnt say what size he put in it. the car is going back up to him monday and this time i am going to watch him do everything to check and see what everything is set at and to see what all he is doing.
By the way i went with an 850 DP becuase that is what holley recommened.

 

Alright i was working on my ar last night and i noticed that the plugs where arcing to the head. the plugs were are arcing from the base of the plug straight to the head on every single plug. it was really fant and you could barely see it but if u look real hard u could see it. its like all the spark wolnt go into the combustion chamber or its blowin back out of the spark plug hole. I have never noticed this until last night cuse i usually dont work on my car late at night. The car dosnt miss or anything though. Has anyone seen this before or know what is causing this. would gaketed plugs solve this problem. I have a full msd ignition digital 6, blaster coil, pro billet distributor. I am also runnin NGK plugs and taylor wires. This could diffantly contribute to my car not meeting its full potential.

 

Are you saying the arcing is between the wire boot and head, or from the plug itself to the head?

If the former, put some dielectric grease on the boots. If the latter, you have a problem with plug grounding to the head.

 

Friend of mine is running basicly the same engine as you only it's a 350, and is turning 11.80's on the motor @ 113-114 mph. Think it's the exact same cam and same cfm carb. He has 1 3/4 headers and dual 3 inch exhaust which replaced the old dual 2.5 system.

 

Your exhaust is too restrictive for starters, if you dont want to go more open after the headers then a cut out would be a great improvement. (i know this has been said, just reiterating)

What with a manual car a LOT of it can be driver... i bet you can knock atleast half a second off with no changes but practice.

 

i wish mine weighed in at 3300 with me in it. i went a 10.94 with a 3800 lb iroc and a ls1

 

Its the plug grounding to the head. What is they best way to fix that? Just add another ground or what?

 

Did you paint your engine block by anychance?, Ive had experience with some high temp paints actually containing metal particles and if it gets around your plugs or wires they actualy cause arking between the painted surface and the plug- ive also seen it from wires to block..

just a thought- as for getting rid of it...-- add a couple of ground wires to your heads...

 

Something is definitely wrong here that combo should go mucha faster,i ran 13.02 with a 383cui XE274 cam 185 heads BM3000 turbine 3.73 gears and ET streets in my 2nd gen,redlight at 5500rpm with a 100shot NOS it made 12.4 i hade 1.8 60foot times i guess it never made more than 400hp you should be making much more HP is the machine healthy you should make check definitely take it to a dyno session maybe !!?
I think you are overgeared a 408 like yours would do better with a gear like 3.42/3.73 something and also i think your heads are to big something like 195/200cc heads would be better you dont get good flowresponse in those heads they are for engines like 434cui and up my 2 oeres worth.

Greatings from Volvo country EC :=)

 

This is very true, I know this from experience. I started going drag racing with my car this summer, and at the begining of the season (May-June) I was running 15.5s with a mostly stock 350 in my Z28 with a 5-spd. By September, I was running down to 14.6... and I made NO changes to the car over the summer.

This might not be the whole reason for your 'slow' times, but could definitely be a big part of it.