This is one of those mods that I consider to be ''all out, race only'' stuff.... if you are driving the car on the street, money spent for power gained, it aint worth it..... that said,,, if you are looking for the absolute last oz. of power that a nailhead has and drive the car racing only,,,, then go for it......:Brow: :Brow: I understand that there is a Pontiac rod that will work,,, and what it does is change the angle of the rod in relation to the crank thru the circle as it turns the crank.... giving a little more power to the crank from the piston....and like Kit said, the pistons , and the balance and clearances have to be redone, neccessitating a run to the bank.... it seems to help a ''short stroke'' engine more than longer stroke engines like the nailhead....more of a small block Chevy trick.... or small block Ford....I would lean to a huffer , turbo, or nitrus instead , to pick up power , for the money spent.... but you would need forged pistons for that too......that is why I always say to build with forged pistons if you can afford it, to start with.... no matter what level the engine you are building is at....then you can always go ahead with what ever mod that you want to do without worrying about the pistons not holding up....
just read in the new buick performance book that the pontiac rods are 6 5/8 long and would hit the oil pan unless you used a 1/4 inch spacer. tom t is running longer rods did he have to move the pan.
Supposedly the perfect rod length/stroke ratio is 1.9. You also must remember the sine angle degrees. Ideally in the lower, middle 15 minute area. Stock the 401/425 is a little over 17 minutes. We went 6.850". I wanted closer to 7". Now the pin still sits below the oil rings so we could have gone even longer. A longer rod also puts less stress on the cylinder walls. Part of the angle in degrees/minutes. Tom T.
what happens when you use a longer rod say 6.535 and turn the crank down to 2.10 for a stroke of 3.79 instead of stock at 3.64. do you think that would work out.
i like do both that rod has a 2.1 journel. stock is 2.25. i would turn it down and offset the crank. 3.79 stroke would give 450 cubes. the longer rod would give me a smaller and lighter piston and a good rod ratio.
Like I said, except for all out racing,,, it aint worth the expense, time and effort....:laugh: :laugh:
doc running out of things to do. running 12.8 at 107mph. 1.85 60ft times.323 gears and a 2-speed tranny. like to go 12.3 et. like you always say dont sell the nailhead short
Damn, that's a good running Nailhead!:TU: Losing 500 pounds should do it. Or find 50 more hp. More compression helps, but it won't help THAT much! What are you running now? Got roller rockers yet? Your 60 ft time seems a bit high for a car in the mid 12's. Consider a good converter from Trishield and some suspension work.
i have 9.75 compression wanted 10 but the machine shop didnt have the pin height right. getting new front springs there real stiff now. could have heated the slicks more. might be another tenth there, 1.75 would be the best i could do with out a better converter like you said. whos trishield?
It's a proven fact that switching to a TH400 is not good for a tenth. The only reason to change is that as you increase the HP the 300 is now at it's breaking point. Meaning it just has to be gone over more often, because of the HP increase, than not. Maybe, every winter to at least freshen it up for the next season. If there are any HP parts available for the 300 they are few & far between. Maybe other parts from other trans. can be modified to work. I don't know of too many that have tried to "Beef-up" the 300. How much ya' willin' to spend tryin' things???? The TH400 weighs more. Takes more HP to operate. Consoles need to be converted. Electrical for kick-down & switch-pitch played with, etc. In general more of a PITA than it's worth. Not that it's not a better trans. it IS. Many do it for the reliability over anything else. Many have been disappointed with the ACTUAL performance. I know some figured a 1/2 second at least & were disappointed with only a tenth or so gain. Now, also, with a lower 1st. gear you end up with traction problems. Not that they can't be overcome, but at what cost. You want to go out & have FUN, isn't what this is all about??? then just do things to help increase the performance. A better solution would be a TH350. But then adapters & the added cost will cost as much, maybe more, than a TH400 swap. This is just my opinion. Just as the longer rods have added another opinion to the 10 already listed. We're not talking Motor Cycles, Indy cars, F1 racing, Pro-Stock or any of the other examples stated. We're talking about a big ole American V-8 that has it's 1st. designs begin in the early 40's before WW11. I know the flaming will start again. You all know who I am, what I do for a living & how to communicate with me. It's out there for ALL to see. You all know my capabilities & experiences & I believe the advice I have given to many has helped many on this & other boards. Who are you Kitabel??? What are or may be your qualifications??? What do you do for a living??? Where can you be reached??? What State or Country do you live in??? Most of us can be reached in some form or another except for you. I apologize if I have offended you in any way. But, where are you comin' from??? What experiences do you have??? Bye for now I'm goin' racin'!!!!!! Tom T.
and the problem I have with the 400 in mine is that I had to drop the tranny down to clear the shifter. where the tailshaft bolts to the tranny it hits the shifter. now I have a vibration problem to fix. uzzled:
If you will shim the body up off the frame 1'' , it will solve that problem.... Yep, GS, that is a strong running nailer.... and you worked hard to get there,,,, now about losing 500 lb,,,,,:laugh: :laugh: I will bet the farm that you have surprised a lot of ''mouth racers'' with that car...:Brow: :Brow:
