03-16-2005 08:09 AM #1
how many rpms can a 350 turn?
Hello my name is mike and im building a 350 for a pulling truck. only one problemi have a small budget. i have a set of 906 vortec heads that i picked up and am having puched to 2.02/1.60 and ned to figure out how many rpms i can turn with a stock bottom end 4 bolt main? if you can help me i would greatly appreciate it, also if you know of any discount suppliers of engine parts that would help alot too!!
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Those heads won't flow a whole past 6000 rpm so there will be no need to turn it harder than that! I wouldn't trust the stock bottom end much over 6000 anyway! Would it do it yes for how long who knows???
To quote Travis on many of his replies....."why?"
Wouldnt you want the engine to run at the torque peak when you are pulling? That is not necessarily max rpm.
mike in tucson
thanks for the info,
it sounds kinda wierd but you dont want to run at peak torque. it took me while to understand it but, wheel speed plays a huge part of the pulling momentum and you are spinning the tires the whole way down and if the tires start to hook up you want the motor to still pull hard at the higher rpm to mainttain the wheel speed,thus more momentum ( my uncle is huge in to dodge truck pulling) when selecting the cam im going to use i am going to get as much torque as possible along with hp
I have turned 7200 rpms consistently with a 350 that i have, 2 bolt main, no main studs, stock crank, scat rods with arp bolts. The motor has been together for 3 years and is on the stand now still intact, just gonna freshen it up. It has seen 7600 several times and has hit 8 at least 5 times. I think people underrate the strength of a properly maintained and well put together motor.
sure you can do all that....if the engine actually made power there it wouldn't live long.....your probably peeking around 6000rpm....If your TRUE power range is 4500-7500 the stock parts would not live long....
Too many variables to argue about, with good rods i think a stock crank could hold 7k. BUt it all depends on so many things......cam, heads, valvetrain, balancing, etc.
Regardless....good luck on this motor.
in a normally aspirated motor in bone stock form the rod is the weakest link.....I am sure the crank could holds it's own too 7,000+ rpms depending on circumstance.....
The 2.02 will kick in at 6,000 rpm's where the 1.94 left off. There is an unanswered question that should be asked. What does this truck weigh anyhow? I mean if you're lugging around 3800 lbs with 33 in. tires, I'd be thinking about a 400 crank to build a little more torque. At any rate try to keep your reciprocating weight down,(ie rims & tire wieght, driveshaft, etc.)
The 170cc intake runners are gonna do you in before the 2.02 valves are gonna do you much good. The 906 head is great for building torque but starts to peter out around 5500 and is all done by 6200.
thanks agian for the help. i was thinking the same about the heads and 170 cc runners hidering me but for now im trying to keep cost dwn untill i get my chassis and drivline ( except motor) setup the way i want it. in the end i'm going to have these heads potedand polished and what ever it takes to get them to flo what i need.adn have a 400 or 383 stroker rotating assembly running about 7500-8000 rpms max but thats a couple years down the road.
the truck will wiegh ina t 5600 lbs i will be pulling in the 5200 wiehgt class but since i am using a small block i am allowed up to 400 lbs extra. i think itts actually an advantage. usually you runn out of traction way before you do power.
once agin thanks