Stroker advice

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CLAY72dart said:
No I bought a pair of 360 915 heads for the build. Is 400 dollars a good amount for them?
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In stock form with a 390 and 10:1 cr with your cam should get you around 1 hp:cid and probably make a 1.2 tq:cid for 390hp/468tq. Good for a burnout machine.
 
rumblefish360 said:
I agree. If your so worried about he cam kit, don’t be. Or sell it.

Decide on the power goals or a ET for the track. That cam is almost perfect for a street stroker and bowl blended 2.02 stock heads. You’ll make a lot of torque and have reasonable HP.

The LSA of 107 is 1* off of the 106 I calculate. It won’t be a noticeable difference changing cams. I’d run it on the 390 mill with bowl ported 2.02 heads and have a blast with it leaving twin tire burn out marks everywhere. 3.55 gear minimum.
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My calculation on LSA using the DV 128 formula and 2.02" intake valves favors a 102° LSA. Pretty tight. But I would also like to see intake valve lift more like 0.540" to enable the air/fuel charge to follow the piston down better. A good flowing head is imperative on a stroked engine.
 
oldkimmer said:
They’re all good. Kim
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I would talk to SCAT. Some people have had broken cranks with Made in China components. Many are cast or forged in China, but machined aand QC/QA verified in America. Much better confidence you will not suffer a catastrphic failure. Cost of the crank is one thing, but it is all the other components including the block that can be destroyed.
 
CLAY72dart said:
The cam was not supposed to be first I just picked it up for 250 bucks and I wanted to get a stroker kit that would work with it.
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People report problems with the flat tappets again lately from Comp. If you keep it, make sure to use an oil for vintage engines with adequate ZDDP in it.
Possibly look into Amsoil Z Rod oil.
 
Dale Davies said:
A small engine is torque limited, so a lower final drive or lower 1st gear is required. A large displacement can use its torque with a higher gear ratio to keep the RPM and noise down and aiding fuel economy.
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I just broke a rib yesterday so I am shorter tempered than normal, Buuuuuttttttt....

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Really? Are you SERIOUS? If you're worried about fuel economy, why the hell are you here? Just get a ****** car and piss off!

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Dale Davies said:
A small engine is torque limited, so a lower final drive or lower 1st gear is required. A large displacement can use its torque with a higher gear ratio to keep the RPM and noise down and aiding fuel economy.
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Kind of, that's more of side effect than the purpose. The purpose is to put the engine in it''s powerband at various road speeds, eg.. say in a drag race from stall to shift points is 2500 rpms wide for both 340 and 440 say 4000 to 6500 rpm vs 3000-5500 rpm obviously the 340 needs more stall and gear than the 440 to put it in it's powerband. But it could be just driving around you want to be able to easily access the powerband at various speeds (gearing)

Think of it this way, Starting at the tire say your putting X hp/tq to the ground at Y speed, so that's the constant between various engines displacements,.The Different displacements and they various efficiencies etc.. with different tq and rpm ratios, no matter what will to equal out with gearing or otherwise your not putting X hp/tq to the ground at Y speed.
 
Dale Davies said:
A small engine is torque limited, so a lower final drive or lower 1st gear is required. A large displacement can use its torque with a higher gear ratio to keep the RPM and noise down and aiding fuel economy.
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That was for 273 (no worries) & it was asked because it was vague and aloof.
I had a feeling the knew where he was going but let loomed for clarification. A zeroing in.
273 said:
Kind of, that's more of side effect than the purpose. The purpose is to put the engine in it''s powerband at various road speeds, eg.. say in a drag race from stall to shift points is 2500 rpms wide for both 340 and 440 say 4000 to 6500 rpm vs 3000-5500 rpm obviously the 340 needs more stall and gear than the 440 to put it in it's powerband. But it could be just driving around you want to be able to easily access the powerband at various speeds (gearing)

Think of it this way, Starting at the tire say your putting X hp/tq to the ground at Y speed, so that's the constant between various engines displacements,.The Different displacements and they various efficiencies etc.. with different tq and rpm ratios, no matter what will to equal out with gearing or otherwise your not putting X hp/tq to the ground at Y speed.
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A better explanation for sure.
 
CLAY72dart said:
I was hoping 4-5 thousand for the engine and another 1500-2000 for the brake kit and I’m trying to find a beefy rear for the car. I will probably just take one from a junkyard rt and make it work.
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You can get a 408 short block at Indy for 3500.
 
rumblefish360 said:
A better explanation for sure.
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Obviously there's tons of variables but using drag racing to narrow it down but any aggressive part/full throttle driving this applies to. Gonna assume two well matched cars of same weight producing near identical 1/4 mile times, mph and very similar at all parts of the track but one has a 340 and the other is a 440.

Now these cars will be putting very similar hp to the ground as each other at the same speeds and the same parts on the track, to be performing the same. The plots of each hp curves in each gear to the ground on the track through on the run will be very similar. Since tire is a constant size, so rpm per mph is fixed, along with hp curve in each gear, so to tq will be then. So the performance to tire is kind of fixed and is the end result and so no matter what comes before it (drivetrain) has to equal out. So each engines with different powerband rpms and torque #'s and gearing performing very similarly has to equal out to the tires to have similar hp/tq curves throughout the run. To perform similarly on track street etc..

Now let's bring some variability into it, now not all cars weigh the same, with still same overall hp curves to the track the hp numbers will be different now but will be within similar power to weight ratios at each point of the curve to give similar performance.

Now let's say there's a difference in weight and different hp curves with different amounts of gearing but similar power et mph, there track curves will vary throughout the run but hp averages will be similar but the relative ratios of tq rpms and gearing will workout to give similar hp average to the tire throughout the run. Etc...

There's a mathematical relationship between gearing rpm and tq, NA tq is highly dependent on cid and so is rpm for a given hp and cid so ultimately displacement and gearing are mathematical related for a given performance.

Does that mean for a given cid e.t. and mph they all need same gear/tire ratio, no cause there's also the variable of efficiency, which is lbs-ft per cid which for most non highly competitive racing 1 to 1.4 gross tq:cid above 1.3 is doing incredibly well and most fall short. But engines of very similar hp and tq:cid but of different sizes and rpm powerbands like 340 vs 440, the ratios of rpm tq and gearing will be very mathematical similar.
 
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Ottmundr said:
I just broke a rib yesterday so I am shorter tempered than normal, Buuuuuttttttt....

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Really? Are you SERIOUS? If you're worried about fuel economy, why the hell are you here? Just get a ****** car and piss off!

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Who knows where the cost of fuel.will end up. Now if a vehicle is a daily driver, fuel economy is more of a concern than a show and shine vehicle or a race vehicle. With drag racing economy is not a concern, but many road and circle track races restrict available fuel, so economy must be considered. Lota stuff goes on in the world whether we are aware of it or care to be aware.
I do appreciate your rebuttal.
 
For many into cars and horsepower it is no different than someone addicted to cigarettes. There is no dollar amount for a pack of cancer sticks that someone addicted is not willing to pay for their fix. None. They will pay whatever it takes so long as they aren’t knocking on deaths door. I’ll keep paying whatever premium costs to get my fix. Fuel economy? Bah!:realcrazy::lol:
 
Alright I have picked up the block. Went with a 360 block with a pair of stock 360 heads that will be ported. I’m just gonna go with the 418 stroker kit with the comp cam and send it with the advice of a mopar machine shop nearby. Also picked up this grill today at Carlisle for 225$ the dart custom. I know I’m wrong but it looks so much better than the other grill.

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CLAY72dart said:
Alright I have picked up the block. Went with a 360 block with a pair of stock 360 heads that will be ported. I’m just gonna go with the 418 stroker kit with the comp cam and send it with the advice of a mopar machine shop nearby. Also picked up this grill today at Carlisle for 225$ the dart custom. I know I’m wrong but it looks so much better than the other grill.

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Good deal... and I did the same thing with My '72 Swinger, swapped to the earlier grille, don't toss Yours tho'!!! Lots of '72 Demon folks looking to resto will want it..
 
CLAY72dart said:
I’ll text him. I’m needing standard work just a bore for the stroker kit and a port on the heads. Then advice to build it.
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Any machinist will need the piston to properly set it up for best results.
Is your assembly in hand? Is it balanced?
 
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