Is it the heads? Cam? Block? How do i know what RPM i can safely go up to? I waas thinking 7000 but i noticed a crate motor that said 5500 rpm max?

thats relative to the air flow of the heads, yet limited by valvetrain. a.k.a. valve float start at about 55-5800 with stock hyd flat tappet lifters and a full rooler setup with girdles will go all the way up like NASCAR engines.

Like Harley said. Cam, intake, heads, exhaust will all limit HP, but ultimately it's the valve train that limits rpm.

So what do you think is a good max RPM for me.

we need to know your specs... rpm limit can be a non-issue depending if your motor can make more power or not. for example, my motor has a roller cam and can spin to 6200, but it only makes power to 5500, so why would i ever spin it that fast?

My wallet has a direct effect on the RPM limit of my motor -- or put another way, if you spin 'er too fast, its gonna cost ya!

I opted to add the AFR rev kit with my new AFR heads which limit's V float and added 700 rpm from 5800 to 6500 and my motor hp raised from 5800 rpm 494 hp to 6300 512hp so that was a gain 18 hp and the kit was 245$ so was it worth it I think so cheep insurance and I am going to run a 6000 or 6100 chip in my rev limiter,Happy Motoring P.S. TT is this going to be a Street or Drag motor ,I have been following along in your post's and I don't think you have ever said what applacation your motor is for ??? maybe clarify,street?, Drag??, combo of both ??I can help If you want I have offered before but NA :confused:and am close...PM me...you me and some other Puget sound guys can get together at the track...The weather is going to change soon I hope:)

I will drive it on the street, but want it built for the drag strip for the most part. I do want to go to the track but am still working out some issues before. After that i will hopefully be going all the time.

The valve spring itself will also limit HP. Some springs can't keep up.

I will drive it on the street, but want it built for the drag strip for the most part. I do want to go to the track but am still working out some issues before. After that i will hopefully be going all the time.


Cool Tom: sounds like your on the right track:yes: Happy Motoring..As stated above intrested in 17 yrs. of experance at the track let me know ..

As suggested, the ability of the engine to flow air, in & out, for making power.

Any engine will rpm into ozone regardless of the equipment attached to it.
It depends on how long it will stay together and how strong the valve springs are.

Frictional horsepower - as rpm's goes higher, friction gains.
Heat - all this friction generates heat, oil burns away, then hot mating surfaces become one.

There was acutally a guy on here a short while back that rev'd his motor up in neutral until it blew. I would contact him, find out what rpm it blew at, and subtract 50-100 !!! :D

Also keep in mind that the higher RPM you go the less miles you will get out a motor before it needs to be refreshed. The higher RPM puts a lot of strain on the bearings and rings forcing engine rebuilds more often. Keep it below 6k-6500 and you should be able to get 100k+ miles out of a good motor.

your cojones

Cool Tom: sounds like your on the right track:yes: Happy Motoring..As stated above intrested in 17 yrs. of experance at the track let me know ..I would definitly like to go to the track with someone who knows what there doing. The engine is almost ready, i do need to take care of some of the rules though. I dont have a nuetral safety switch, but i do have a toggle on the ignition does that count?

I would definitly like to go to the track with someone who knows what there doing. The engine is almost ready, i do need to take care of some of the rules though. I dont have a nuetral safety switch, but i do have a toggle on the ignition does that count?


Tom Please PM me ,I am going TKO 600 and have all that auto stuff , maybe I can help ,I would love to help,I can help get the most out of your setup,along with Fred I am sure he would love to help too right Fred.. I am setting my car up for mostly street but will run it down the track a time or two,I have all my Drag stuff I am going to eather sell or put in another car,I havn't made my mind up on that yet I just want to get my new setup in S/B by end of May Happy Motoring

Coates Rotary Valve Heads have been trying to get this idea off the ground commercially for quite a while and haven't done it yet..

http://www.coatesengine.com/technology.html

The head consist's of two slotted rotary valve cams that do completely away w/ the usual poppet style valves used everywhere. And they tested a set of their heads on a stock SB Ford that I figure was a 5.0(??), and it hit 14,000 rpm or so!!

pdq67