Looking for more 408 pull at the big end?

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70aarcuda said:
so....our 410 in our 71 Dart has run a best of 10.38 @ 127 here in Vegas air....shifting a 6500 rpm and running it out the back door at 6900 rpm....

So you are saying we should shift no higher then 5800 rpm...and it will run faster?

in the desert we dont get to see cows....
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First of all you didn't mention your cylinder heads. I bet they aren't unported Edelbrocks.
Second of all there are exceptions to every rule. Third if I was racing you and told you to shift @ 5800 to go faster I would win. J.Rob
 
RAMM said:
The camshaft isn't the problem. There isn't a non-offset rocker head that will support a 4" stroker to spin much higher than 5500-5800. You can cam it, header it, single plane it, carb it, till the cows come home, won't help. Part of my mild disdain for strokers is exactly this. J.Rob
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Your quote says there is not a non offset rocker head that will support a 4 inch storker over 5800....Now you are getting specific....LOL...Cause we are using non offset heads...
yes..they are ported eddy heads....
 
MichaelB. said:
If I were to tune up something (other than the driver) for more top end charge what would you go for 1st?
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You mention "Tune up", not "start replacing"... I'd do as "replicaracer43" mentioned, then I'd "add" a cold air intake. And dial it in some more. Unless you got money to burn!
 
Now that you have stated the heads just have a basic “ shine job” i would send them to Modern and get themCNC’ ed
Trust me that will yield results you will be tickled with.
Then get an 8 inch convertor done up. It will street drive better than that sloppy TCI, and be WAY faster
 
Th OP's memory of 195cc int ports may be a little off if they are supposedly stock. Now Hughes is already questionable in my book... and what a "clean up" means could be anything to nothing... and so "195" may have just been the thermostat rating he uses.lol .
 
MichaelB. said:
TCI Super Street Fighter 3500 stall converter
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I'd say it's the convertor. That one is a primarily a street unit, poorly made and is slippery. It's showing around 10% slippage now, and from what you commented the performance has been dropping. I'd bet in a 1/4 mile run it would be a bit more as it gets hot. Get a decent semi-custom or custom unit and you'll get a bit of that mph back.
 
MichaelB. said:
So I built a 408 a few years ago. Started out just looking for under 500HP. About half way through the build I got a little amped up and went farther. Ended up with Eddy Magnum heads, polished massaged & deep port matched to an airgap by Hughes, then bolted on 1 7/8 race headers by TTi with 3.5 collector, KB forged pistons (11.0:1) Big Howard's cam (Duration @ .050": 248I/254E, Lift: .578"I/.590"E, Lobe separation 108) MSD and a 850 Dominator. Put a 100 shot plate system too. Might be too much for my Eagle cast crank with Eagle I beams (whoops got them 1st).

Anyhow went to the strip & ran some mild 1/8 mile all motor passes while breaking it in. Car launches great on 28 inch slicks 4:10 gearset 3500 stall 904. Three passes net nearly identical traps: 60 ft = 1.5, 330 = 4.7, 1/8th = 7.4 @ 91MPH consistently. Ninety one... I was looking for more in the 100MPH range. Don't you agree?

Car is pulling like a freight train. No skips or hiccups, great smooth power up to 6000 RPM shifts. I just feel like the trap speed is showing a weakness... If I were to tune up something (other than the driver) for more top end charge what would you go for 1st?
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My previous motor was almost identical to yours Except I have ported Edelbrocks from Ryan @ ShadyDell and an 8" converter (248/254 comp street roller cam, 10.8:1 compression, 750dp, victor intake). That motor ran consistent 6.7's in the 1/8th at about 100mph.

If you port the heads you will pick up the power (MPH), the converter will help with the ET......then that Eagle cast crank will probably break....not to be a downer, but those are not known for their strength. The Eagle forged cranks are fine (that is what my 410 had in it), but Eagles cast cranks have had issues.
 
We must be crazy to build mopars
Spend a ton and Same/less power stock stroke 350 with good heads
No head equals nopowa!!!
 
If you ever buy a turbo action street fighter.... you have to know there are 3 different versions...loose, medium, tight.

Tight is the only one worth a **** for a dual purpose car.
 
RAMM said:
The camshaft isn't the problem. There isn't a non-offset rocker head that will support a 4" stroker to spin much higher than 5500-5800. You can cam it, header it, single plane it, carb it, till the cows come home, won't help. Part of my mild disdain for strokers is exactly this. J.Rob
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WHAT!!!!!!!!!!! LMAO.
 
Something wrong with the tune... and are you using the NOS shot on that run?????
Have a friend that run 7.3's in the 1/8 with a 1.6 60 ft. stock stroke 340 with eddy heads, cam around .500 lift. pump gas, 4.11 gears and a coan converter. Your combo should make more power than his easily with the NOS shot.
 
318willrun said:
Something wrong with the tune... and are you using the NOS shot on that run?????
Have a friend that run 7.3's in the 1/8 with a 1.6 60 ft. stock stroke 340 with eddy heads, cam around .500 lift. pump gas, 4.11 gears and a coan converter. Your combo should make more power than his easily with the NOS shot.
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I dont think he was squirtin it.
Dont think i even would with that cheezy convertor
 
MOPAROFFICIAL said:
If you ever buy a turbo action street fighter.... you have to know there are 3 different versions...loose, medium, tight.

Tight is the only one worth a **** for a dual purpose car.
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But he said TCI. Only one type - and they are not really efficient. Not a good race unit at all. I ran them myself - in the mid 90s... Way better out there.
 
RAMM said:
The camshaft isn't the problem. There isn't a non-offset rocker head that will support a 4" stroker to spin much higher than 5500-5800. You can cam it, header it, single plane it, carb it, till the cows come home, won't help. Part of my mild disdain for strokers is exactly this. J.Rob
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I’m not sure what the definition of “much higher than” but mine runs best and pulls hard to 6300-6400 rpm. With nowhere near the intake or exhaust flow that is very easily accomplished. Stock casting intake and exhaust manifolds.
 
I'm guessing tune and converter. Timing? Air fuel ratios going down the track? Getting full throttle to carb? Cold air intake?
 
318willrun said:
Something wrong with the tune... and are you using the NOS shot on that run????? ... Your combo should make more power than his easily with the NOS shot.
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Nah I did not put any juice to it with the cast crank. 'Fraid to!

Walker434 said:
I'm guessing tune and converter. Timing? Air fuel ratios going down the track? Getting full throttle to carb? Cold air intake?
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Alright, I think I will start there. Enough of us are thinking "tune" so let me tinker without swapping parts 1st. As far as cold air... That is the car in my profile pic. Hemi hood scoop right to air intake. I think its getting some cold air.

The timing is pretty stout as I have it. It nearly effects cranking speed on start up.
 
Duane said:
Don,t hold back!! Tell him what your car runs lol.
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I’m not sure it’s worth the time. Some guys test things on a dyno and say yep that doesn’t work. I’m sure he knows what my car and my sons car run with stock pushrod position Edelbrock heads.
 
pittsburghracer said:
I’m not sure it’s worth the time. Some guys test things on a dyno and say yep that doesn’t work. I’m sure he knows what my car and my sons car run with stock pushrod position Edelbrock heads.
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What displacements? I seem to recall a stock stroke configuration.

My comments were based on where the HP peaks and the shape of the curve which is what a dyno can tell you quite easily. J.Rob
 
RAMM said:
What displacements? I seem to recall a stock stroke configuration.

My comments were based on where the HP peaks and the shape of the curve which is what a dyno can tell you quite easily. J.Rob
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4 inch stroke (408)

Edelbrock headed 408
6.143@110.85 mph
9.73@135.05 mph shifting at 6700 RPM
2860 pounds Powerglide

10.08 in my Sons car at 3200 pounds 727 transmission.

This engine was in need of its 4th rebuild at this time and the bores were shot.
 
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