Cylinder head discussion 340 with stock above deck pistons

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One of the most fun builds I ever did and charged my friend 5.00 to do it (5.00 worth of jawbreakers)
340 with stock crank
J or X heads slightly polished
484 lift purple shaft hyd cam
Port o sonic intake
750 double pump Holley
Stock 10.5-1 pistons
Stock rods
1 7/8 headers
727 with J converter
3200 pound 72 duster
Super stock springs
10 M/T slicks
Low 12.2’s new driver 2nd time out
I built this engine with friends in his pool room. We laughed and hollered the whole time eating jawbreakers.
 
nfhDODGEnfh said:
I do have adjustable shocks front and rear in the car. The tire size is 235 60 15 so they aren't big tires and I've been considering adding clatracks. That being said I haven't had tire shake or jump yet off the line. It just plants and I go. This season I will be setting my 2 step up so I can dial my launch rpm in better.
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That tire size is plenty for a 340.
 
Not with a stick car with 235 drag radials. He is dropping the clutch at 2500, bogging the engine down and driving out to a 2.0 60 foot. He needs to come out higher and manage the clutch slip with a bias ply slick and get it down to at least a 1.70 60 foot and the car should run in the 12's. Clutch management, either a lot of foot control or a Clutch Tamer or a Soft-Loc clutch. He needs to slip the clutch and keep the engine at or above peak torque until the rpm's and tire speed match up. Think of using the clutch like a high stall torque converter.
 
If you can’t suspension tune a 12 second car you better break out the books. Slipping the clutch is a bandaid. Floor it and dump it
 
19DART66 said:
Not with a stick car with 235 drag radials. He is dropping the clutch at 2500, bogging the engine down and driving out to a 2.0 60 foot. He needs to come out higher and manage the clutch slip with a bias ply slick and get it down to at least a 1.70 60 foot and the car should run in the 12's. Clutch management, either a lot of foot control or a Clutch Tamer or a Soft-Loc clutch. He needs to slip the clutch and keep the engine at or above peak torque until the rpm's and tire speed match up. Think of using the clutch like a high stall torque converter.
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Yes. But the OP will listen to every rail bird out there thats never had a stick.

The snubber needs to find a different home. If he doesn't have double adjustable shocks and has single adjustable shocks...no one can tune those.

The least he needs is a clutch tamer. He's going to have a hell of a time leaving on a two step with just using his leg unless he has 10 years of practice at it and even then not having a ST or better yet a soft lock clutch.

In fact I'd say wait on the heads and get a clutch and shocks. Far better money spent on that than heads.

But what do I know???
 
I am guessing it's been a very long time since you have raced a clutch car. The days of flooring it and dropping the clutch with a 3600 lbs pressure plate are long gone unless you really like destroying driveline parts. It's all about clutch management now.
 
Good advice in the thread.
Make the chassis upgrades before you worry about applying more power.
You will pick up the most ET that way.
 
As mentioned, they just need practice.
99% of their launches are on the street.
Put them on a sticky track, side stepping the clutch at 3500, resulting in breakage, bog, missed shifts, red lite, yep, lol
They need guidance, and they're getting that now . lol
 
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19DART66 said:
I am guessing it's been a very long time since you have raced a clutch car. The days of flooring it and dropping the clutch with a 3600 lbs pressure plate are long gone unless you really like destroying driveline parts. It's all about clutch management now.
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I had a 3400 pound pressure plate back in the 1970’s that I raced on both the streets and drag strip. Don’t say it can’t be done.
 
Inertia said:
As mentioned, they just need practice.
99% of their launches are on the street.
Put them on a sticky track, side stepping the clutch at 3500, resulting in breakage, bog, missed shifts, red lite, yep, lol
They need guidance, and their getting that now . lol
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Yup.
Y
 
pittsburghracer said:
I had a 3400 pound pressure plate back in the 1970’s that I raced on both the streets and drag strip. Don’t say it can’t be done.
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It can be done. It's just slow and breaks parts. No one in their right mind does **** like that today but head to a track with a stick race and you'll see that 1970's junk still going slow and breaking parts.
 
The original intent was a discussion about heads. My car is not strictly a drag car it's a street car I like to take to the strip. I don't even think most people responding to this are reading the whole thread. Seems like you are just arguing with each other and making assumptions about driving ability. As I stated before it's been down the 1/4 at one event where I made maybe 9 passes. The track we had in town shut down but I raced there for 4 seasons and made 150 or more passes on a 330' track. Even though it's a short track you still get to practice launches. That was before I got radial drag slicks and nitrous. Now I am hoping to get a bit more power out of it. I am aware that I can get my 60' better but rather than starting to high and breaking things and working down to the right launch rpm I am starting low and working my way up. This season is coming up soon and hopefully I'll get to the track 3 or 4 times. I haven't started slipping the clutch on launch yet because I need to raise the rpm more on launch before that will realistically help. At the old 330' track with bfg radials I couldn't launch more than 1800 without spinning the tires badly. So I started there and kept increasing it a little bit at a time, haven't found that upper limit of suspension or tire grip yet. Then I'll start to slip the clutch on launch. I am getting good ideas from reading some of the comments but it seems like a lot of assumptions are being made that could be cleared up if people were reading the whole thread.
 
Pittsburgh, Didn't we all run that junk back in the 70's when we didn't know any better, and we broke a lot of parts too. Just like torque converters have come a long way since then, so has clutch technology. I haven't broken a part in my 4spd street Dart in at least 10 years and probably longer and it leaves with the wheels up more often than not, nowhere near as high or as quick as your car, but mine is a streetcar on 9 inch slicks, not a full on race car on 14 inch slicks.
 
Inertia said:
Thanks folks, These trips to the track with street tires and 3.55 are few and far between.
I don't have much experience with nitrous, so letting those that know give guidance.
Mikes a quick learner, and eager for knowledge.
The cars plant, launch really well, - till we put decent gearsets in, with decent tires, I don't expect "track" times.
One of my son's hi rpm launches, broke an axle, looked lazer cut, lol.
Their 3 trips to the track has whet their appetites, and they can certainly learn lots here.
Thank-you .
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If you're really gonna spray it, the best advice I have is run it a little fat. Not pig rich, just a little fat.
 
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nfhDODGEnfh said:
The original intent was a discussion about heads. My car is not strictly a drag car it's a street car I like to take to the strip. I don't even think most people responding to this are reading the whole thread. Seems like you are just arguing with each other and making assumptions about driving ability. As I stated before it's been down the 1/4 at one event where I made maybe 9 passes. The track we had in town shut down but I raced there for 4 seasons and made 150 or more passes on a 330' track. Even though it's a short track you still get to practice launches. That was before I got radial drag slicks and nitrous. Now I am hoping to get a bit more power out of it. I am aware that I can get my 60' better but rather than starting to high and breaking things and working down to the right launch rpm I am starting low and working my way up. This season is coming up soon and hopefully I'll get to the track 3 or 4 times. I haven't started slipping the clutch on launch yet because I need to raise the rpm more on launch before that will realistically help. At the old 330' track with bfg radials I couldn't launch more than 1800 without spinning the tires badly. So I started there and kept increasing it a little bit at a time, haven't found that upper limit of suspension or tire grip yet. Then I'll start to slip the clutch on launch. I am getting good ideas from reading some of the comments but it seems like a lot of assumptions are being made that could be cleared up if people were reading the whole thread.
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Some of us, especially the guys who raced (and probably still do ) sticks are telling you you dont have a horsepower problem. Yet you want to make more power that you can't deal with. I said go buy some Bloomer heads. You can use everything else you have.

Making more power right now ain't your problem, but you don't want to hear that. And I've read the entire thread.

You are getting the answers you need but not what you want. Maybe YOU need to rethink what you are doing because I won't say go make more power until you fix the basics first.

@toolmanmike here is the perfect example of why I always say make the most power you can because 300 or 400 or 1000 horse pressures is never enough.
 
RustyRatRod said:
If you're really gonna spray it, the nest advice I have is run it a little fat. Not pig rich, just a little fat.
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Absolutely.

If I'd known he was gonna spray it, I woulda opened the ring gap a little.
I shoulda expected it tho, the pair of them are just like me.
I already got a stroker in the works for the other one, now this one's gotta catch up . lol
Not far from the tree .
Cheers.
 
19DART66 said:
Pittsburgh, Didn't we all run that junk back in the 70's when we didn't know any better, and we broke a lot of parts too. Just like torque converters have come a long way since then, so has clutch technology. I haven't broken a part in my 4spd street Dart in at least 10 years and probably longer and it leaves with the wheels up more often than not, nowhere near as high or as quick as your car, but mine is a streetcar on 9 inch slicks, not a full on race car on 14 inch slicks.
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Break it, fix it, repeat. I had a Lakewood bellhousing, aftermarket clutch and pressure plate, 3 inch custom made driveshaft, Lakewood ujoints, 2 sets of gears after breaking every weak link possible. Fought pinion angle issues before we ever knew to measure it. Good old Direct Connection failed to notify us that installing super stock springs threw your pinion up 8-10 degrees. That was a fun learning experience. This guys feelings are a little soft so I’ll let you guys tell him how to fix his car. Peace out.
 
I would not buy open chamber Eddys required to clear your above deck pistons because later if you want to build a zero deck piston with ideal quench then open chamber heads wont allow you to get the quench. Maybe closed chamber Eddys or Trick Flows run thicker head gasket to clear pistons. But then might need thicker intake gaskets to make it work.

Aluminum heads chop massive weight off front of car thats a huge benefit.

Now back to the your car should be faster you don't need heads discussion....
 
Another thing is they run with full exhaust, crinkle bend 2 1/2" pipes to the back.
I encouraged they open them up, but . .
Then we can go from there, baseline.
I just spent too much time roundy-round.
This yr dragstrip.
 
340sFastback said:
I would not buy open chamber Eddys required to clear your above deck pistons because later if you want to build a zero deck piston with ideal quench then open chamber heads wont allow you to get the quench. Maybe closed chamber Eddys or Trick Flows run thicker head gasket to clear pistons. But then might need thicker intake gaskets to make it work.

Aluminum heads chop massive weight off front of car thats a huge benefit.

Now back to the your car should be faster you don't need heads discussion....
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Thanks for the input about heads, I'm also considering port matching my current j heads and doing a light blend and polish to increase a bit of flow without changing things to drastically. As for my car going faster I really need to take it to the track again and hit it harder off the line as I don't think I've hit the limit of my tires or suspension just yet. My trap rpm was a bit low too, I think I was crossing the line around 5000rpm. Might try a set of 3.9 gears and see if that does the trick to get my rpm up 500 ish more when I'm crossing the line. It should help me get out of the hole a bit quicker too. I want to take small adjustments to get the car faster so I'll know what worked or didn't work when I try it. I've also put thought into a double pumper vs vacuum secondary. Right now my 3310 has the lightest spring and has a decent WOT afr. I could bring jets to the track and try leaning it out to see if I get more mph, the tough part is getting to the track. I live on and island and I have to go to the mainland to get to a track. Ends up being am expensive trip and it can't be done same day as the races start in the evening. So far I trailer my car there. I wish the track in my town wasn't torn down for condos, what a damn shame........
 
Inertia said:
Another thing is they run with full exhaust, crinkle bend 2 1/2" pipes to the back.
I encouraged they open them up, but . .
Then we can go from there, baseline.
I just spent too much time roundy-round.
This yr dragstrip.
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@Inertia The Friday night street legal shoot out we participate in to do these 1/4 mile passes at mission raceway does NOT allow open headers or un muffled cars. It's a street car shootout where it's always heads up and people are just racing their cars and having fun. You can get 9 or 10 passes in while they are open because it's not a bracket race, just heads up to get people off the street and into a track where they can go all out safely.
 
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nfhDODGEnfh said:
The Friday night street legal shoot out we participate in to do these 1/4 mile passes at mission raceway does NOT allow open headers or un muffled cars. It's a street car shootout where it's always heads up and people are just racing their cars and having fun. You can get 9 or 10 passes in while they are open because it's not a bracket race, just heads up to get people off the street and into a track where they can go all out safely.
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Uncorking the exhaust requires another carb tune unless its tuned wrong now and you get lucky.
Many uncork the exhaust and go slower.
 
a-bodyguy said:
Uncorking the exhaust requires another carb tune unless its tuned wrong now and you get lucky.
Many uncork the exhaust and go slower.
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I tried that back in the day. I put headers on my 340 Challenger, opened them up at the track and went slower. Without rejetting of course.
 
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