Rev limiting problem

[Carb'dCobra]

Hey guys I just wanted to make sure of something. My car's powerband runs out at about 7000, and the valve train itself will take 8k, however it's somehow limited to 5900. I have a Mallory dual-point distributor and an MSD blaster ignition. I believe that whats happening is the ignition is dual firing because of the dual points in the distributor (blaster is an inductive ignition) and this is why it's doing that, and might also cause the car to be running rich.

Any thoughts?

 

[25thmustang]

A B cam and E7s and you make power to 7000 RPM???

 

[310stanger]

A B cam and E7s and you make power to 7000 RPM???

my car wont do that and i have the trickflow package with track heat spring upgrade! lol

 

[Daggar]

To answer your question though....

The stock EEC's...

Nevermind... I see that you're carbed. Try a hotter coil or closing the gap on your plugs a bit.

Otherwise, your cam is just running out of steam like what is suggested by the others.

 

[Modular2v]

why is that combo being taken to 7000RPMS anyway?

 

[Carb'dCobra]

to answer your questions. obviously the heads are not still stock. The exhaust runners are fully ported and hand polished, the intake runners are port matched to the manifold, the block is cryo-treated, 6061-t6 pistons, billet rods, custom cut and pressed crank, dyno-tuned exhaust (dyno tuned to a holley 4150 race carb, but still), SVO B351 rockers (1.6's), manley stainless steel valves, and a main cap girdle. I think the motor can handle 7000

 

[Carb'dCobra]

Remember, I said about 7000, specifically it's around 67-6800.

 

[stangjunkie]

... put it on a dyno... sometimes it feels like the car is still pulling even thoug you make more power at lower rpm so you may be better off shifting sooner... i couldn't imagine taking my motor up that high whenever i beat on it.

 

[25thmustang]

I have a set of not stock E7s and can say I shift mine high at 5600-5800 RPM... Even with a B cam I cant see much over 6000 RPM. Sure your block and stuff can HANDLE 7000 RPM, but making power that high and actually benefitting from it is a whole other story!

I say figure out your rev limiter issue, but DONT spin that motor to 7000+ RPM.

 

[795.0pacecar]

I'm still trying to figure out why you used a points ignition.

 

[speedytang]

I am still trying to figure out how he thinks it would rev over 6200 rpm anyways. You went points which I had dual points in all my old vettes and they still would not rev over 6k rpm because they would jump. The other questions is you went points but do you still have the stock computer hooked up?

 

[krallman]

id say your biggest limiting factor would be the distributor. after what you have already done to it why haven't you gone with a electronic l.e.d bling bling distributor

 

[Carb'dCobra]

I plan on it, but when I was converting the motor to carbureted, it was, to say the least, a budget build-up. I plan on getting a Mallory Unilite paired with an MSD 6A, and probably a 6BTM when I go forced induction.

By the way, to answer speedytang, the stock computer is on my dresser in my bedroom lol, and the original wiring harness (in its entirety) is at a City of Tampa landfill.

 

[stang8urimport]

BILLET rods are NOT part of a "budget build-up"

 

[Carb'dCobra]

Really? no-s**t? Well I guess neither are billet aluminum slugs, a Bi-Lo custom crank, or block cryogenic treatment, right? The motor was like that when I bought it. I don't wanna come off as an ass, and I assume you don't know the whole story...

The motor used to be carbureted before, but with a holley 750cfm race hp 4150. then the guy made it EFI, but he did a hack job on it (it was yanked out of a 88 GT). The guy was so displeased with this setup (it seemed to have lost a great amount of power... I wonder why?), so he sold it to me for 1700 after I talked him down for about an hour from 2300.(bare in mind, the body was in bad shape to say the least). So I bought it and just within the last 3 months, I've converted it back to carbureted, but with a 4160 model carb. I plan on having it shipped to my station, converting it to a D.P. carb and putting a Dyers 6-71 supercharger on it when I get back from Basic and AIT.

 

[stang8urimport]

What makes you think your valvetrain will hold up to your claimed 8000 rpm? Unless you're runnin an R block or Dart, I doubt it will last very long. 8K is for Dart blocked, billet crank and rods setups. Not Stock block with Billet rods (why waste the money when you have a STOCK BLOCK), are your "custom" crank. E7's at that. No set of E7s have the airflow to work at that high of an RPM range, and def. not yoru B cam.

 

[Xtreme Limits]

dude first all dont yell at others and think u know all that,,,k,,, first off fine so your short block can hold 7000,BUT WITH B CAM AND PORTED E7's youll never rev too 7000! you need a big set of aftermarket heads and a wayyy bigger cam , anyway as far as your problem get a new distributor and your motor will rev out too 6000-6300 max;(thats were youll float the valves becuase of your cam and stock lifters).........hope that clears it up for u

Really? no-s**t? Well I guess neither are billet aluminum slugs, a Bi-Lo custom crank, or block cryogenic treatment, right? The motor was like that when I bought it. I don't wanna come off as an ass, and I assume you don't know the whole story...

The motor used to be carbureted before, but with a holley 750cfm race hp 4150. then the guy made it EFI, but he did a hack job on it (it was yanked out of a 88 GT). The guy was so displeased with this setup (it seemed to have lost a great amount of power... I wonder why?), so he sold it to me for 1700 after I talked him down for about an hour from 2300.(bare in mind, the body was in bad shape to say the least). So I bought it and just within the last 3 months, I've converted it back to carbureted, but with a 4160 model carb. I plan on having it shipped to my station, converting it to a D.P. carb and putting a Dyers 6-71 supercharger on it when I get back from Basic and AIT.

 

[seijirou]

Opinions are like...
Well carb'd you know how it goes.
I don't think that combo will make any power at 7 either but a stock 5.0 will twist up to 7 without a rev limiter. Physically getting there isn't hard.

So the question is, if you are in neutral and step on the gas, are you hitting a wall at 5900? Is that the problem that I think you're trying to get the answer to?

If so, I would look at that points distributor setup that you have.

 

[795.0pacecar]

original wiring harness (in its entirety) is at a City of Tampa landfill.

Bad move, you can get a pretty decent chunk of change for a complete wiring harness. Unless it was all hacked up, then I would have saved it for the connectors and what not.

 

[Carb'dCobra]

So the question is, if you are in neutral and step on the gas, are you hitting a wall at 5900?

Yes lol. Oh and by the way, the harness was trash bro, trust me.