[308man]

I am looking to build a new engine for truck pulling. I would like to stay with a dive block. I hear alot of discussion about not turning larger strokers (530" - 550") at high rpms. I would like to be able to run 7000-8000 rpms with some extreme reliabilty. I would like to stay around 10.5-11.5 com and run on pump gas 93 octane is this possible?

 

[White Lightning]

IMHO, trying to turn all that mass at that RPM is not only next to impossible, but also unnecessary. An engine of those cubes doesn't need to turn a high R to make the kind of power that you'll need.....IMHO
Rob

 

[fireballferkey]

Personally the best motors I have ever had only turned up a max of 6,200 and were in very light cars 2200lbs or so.... but as stated above thats a bad Idea Not impossiable just not necassary. Is there a reason your tryn to get one to turn that high?

 

[EWmudracing]

i believe if its built right turn it what you need to because in any kind of pulling or mud racing rpms mean wheel speed and youve got to have it just put good parts in it

 

[308man]

Pulling has a lot to do with wheel speed. The rpms allow you a greater range of speeds within a gear. This is just my opinion and other pullers may disagree. My current engine is a 460 with trw forged domed pistons, arp wave lock rod bolts and the rest is stock. I consistantly turn 6500-7200 with this setup. I have spun a rod bearing once but it had to do with an oil pump failure. I do however desire reliabilty more than high rpms. Suggestions on a quality kit that would turn say up to 7000 reliably.

 

[White Lightning]

I understand what you're saying about wheel speed, but wheel speed can be obtained from final ratio gearing IF you have enough torque to turn it, and to obtain that amount of available torque all you need is enough cubic inches and/or power adders. The whole reason for turning an engine at a high RPM is to pass a certain amount of fuel through it in order to produce a certain BTU/work ratio. Small cubic inch motors, theroetically, can produce the same #'s as a larger cubic inch engine but you have to pass the same amount of air/fuel through it as the bigger motor thus the need for more RPM's. Large cube engines can do this at a part saving lower RPM. Pounds of fuel per hour....lbs./hr is what determins the "work" produced.
Once again, 7K long term RPM is NOT recomended on ANY long stroke engine. You may get a properly built long stroke engine to turn a high RPM for SHORT periods of time (eg. 30 seconds of drag racing) but it takes it's toll. Hope this helps.
Rob

 

[bigblok86ranger]

I am looking to build a new engine for truck pulling. I would like to stay with a dive block. I hear alot of discussion about not turning larger strokers (530" - 550") at high rpms. I would like to be able to run 7000-8000 rpms with some extreme reliabilty. I would like to stay around 10.5-11.5 com and run on pump gas 93 octane is this possible?

I would contact Paul Kane he is familiar making these engine reliable at higher rpm's. I think if you stay with a 4.300" stroke, good rods, and balance job you could make it live. Of course valvetrain will also need to be strong. I think you will be changing springs often and a good amount of maintenence but sure it can be done. With oiling mods done and previous things mentioned I think you will be spending a good amount of money on the top-end ei; titanium valves, retainers...

 

[MrScharfenberger]

This will be admitting ignorance but here it goes anyway. I have a SVO cast stroker 4.3 crank (521 cid at .030 over), Eagle H-beam rods and J&E 12.5 to 1 compression pistons. The Lunati solid roller cam that I stuffed in it (complete with the Lunati recommended valve springs, retainers and with works) said it was good up to 7800 rpm. So being the fool that I am I stuffed an 8000 rpm rev limit chip (or pill as they call them) into my 6AL box and hung that sucker out to 7800 rpm all the time. Hell I've bounced off the 8000 rpm rev limiter a lot. HOWEVER... Since I've been on this forum I discovered that I wasn't doing myself or my motor any good doing this. The dyno said my peak torque was at 6450 rpm. Since I've been on here and have been schooled I've been shifting it at 6500 rpm and yes... I was a hair quicker that way (but 7900 rpm sure sounds bad ***!!). Anyway my point being maybe I have just been lucky but I ran the wee out of the thing all the way up to 8000 rpm with a cast crank and a 2 bolt main. Nothing has exploded yet and my rocket pig weighs in at 4800 lbs. It has even survived on the 325 shot of nitrous that is ooooo sooo fun to hit (everybody needs 1000hp. I highly recommend it). So I'm going with the some of the guys on this one. Buy good parts. Get a 4 bolt main. And hang the f*ck on!! These 460's are wicked pieces of iron. I'll never run anything else. I'm sold.

 

[EWmudracing]

now i may not know as much as a lot of you guys but lets just say a good scat steel crank and h beam rods are in my opinion good for the 7-8000 hes looking for and doesnt a good set of say scj iron heads make there best power at 7000+ rpms not trying to argue by any means more or less just trying to learn

 

[bigblok86ranger]

I have read some of the pullers engine builds and some of those guys are spinning a factory cast crank to nearly 9000 rpm's and making ~800 hp. They have all had oiling mods that are outlined on Paul Kanes Website done to achieve reliability that is why I say contact him.