Engine RPM?

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MOPARJ

MOPARJ

What can I upgrade now?
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I recently dropped in my newly rebuilt 318, 73 model year, with the stock forged rods, slight overbore, a very smalll amount milled of the heads and a XE268 cam(.477/.480), in conjunction with stock compression pistons. i run Hooker headers and a Performer intake and 600 cfm carb. The valve train (pushrods,shafts, rockers, ect.) are MP replacments. I am running the recommended Comp valve springs.

I have only turned this motor to 4,000 rpm so far, as I still only have 350 miles on the motor. For instance, when at the drags, what is safe maximum RPM I should shift at or allow the motor to rev to? I would just like some opinions on what people think is acceptable for a 318 with hotter cam and rebuilt bottom end with similar to stock components.
 
I wouldn't be afraid to turn it 5500-6000. That cam should get you close to that. The intake would probably die around 5500 anyways. Vary the shift points at the track to see what the car likes.

As far as the old 500 mile break in... I NEVER do that. I've had plenty of BBC's that got the cam broken in and first duty was a 7K RPM burnout... much to my neighbors displeasure. :bootysha: Break in the cam and go beat on it. That 500 mile deal was because machining tolerances were not vary accurate. Gives the metal time to wear off the high spots so to speak. With tooling now days, no need for the break in IMHO.
 
MoparBrit said:
How do you like that cam in the 318? How's the idle, choppy or smooth? Vacuum?

Cheers
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The cam does have a lopey idle, but not radically. Vaccuum is diminished, probably 12-13hg, but my power brakes still work good. The motor sounds awesome and performs well, even with the stock converter and high gear. The power really comes on around 2,000 rpm, although there is still great torque. I wouldn't go any higher on a stock compression 318 though. Great cam!!
 
crackedback said:
I wouldn't be afraid to turn it 5500-6000. That cam should get you close to that. The intake would probably die around 5500 anyways. Vary the shift points at the track to see what the car likes.

As far as the old 500 mile break in... I NEVER do that. I've had plenty of BBC's that got the cam broken in and first duty was a 7K RPM burnout... much to my neighbors displeasure. :bootysha: Break in the cam and go beat on it. That 500 mile deal was because machining tolerances were not vary accurate. Gives the metal time to wear off the high spots so to speak. With tooling now days, no need for the break in IMHO.
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I agree, Rob, just haven't had a long enough stretch of road yet to really ring the beast out. Lol. I dont want to shift manually, as the trans shifts harder with the TF2 kit, even though, some of the components are left out of the kit. Im afraid the harder shifts may destroy the 7 1/4, even though it seems solid and makes no noise. When it shifts automatically, it doesnt shift as hard. I dont floor it until its rolling a bit, so I dont get too good of a grip and rip the rear out. I am extra careful until I get the new rear in a few months.
 
6500 with cast crank and stock rods is where i,d set the rev limiter. is your cam still in powerband that high?
 
Reconditioned rods....dont know about the bolts. A builder put my bottom end together.....hopefully, they weren't stretched beyond imagination.....
 
If they're reconditioned, they SHOULD have new rod bolts. Your bottom end should be good to 6500 rpm but with that cam, I see no reason to spin it that high. Your valves will most likley float and your cam be way out of it's powerband by 6000 rpm anyway. I'd start shifting at 5500 and move up in 100rpm increments until it slows down or you feel the valves start to float.
 
FWIW, I have the XE268H cam in my 360 and it pulls right to my self imposed 6500 rpm limit though the power does start to drop off just past 6000. The cam is rated for 1600-5800.

My engine has 10.6:1 compression, idles smoothly and pulls 13-14"Hg vacuum.
 
Thanks for the answer. Know it is a bit of a cheek to ask on your question post, but combo is about the same as my (looking like years down the road) potential combo. Cheers
 
If you are using stock replacement cast pistons (Badger or Silv-O-Lite) I'd say 6000 is about the max if long term reliability is important. You will be intake limited by then anyhow.
 
C130 Chief said:
If you are using stock replacement cast pistons (Badger or Silv-O-Lite) I'd say 6000 is about the max if long term reliability is important. You will be intake limited by then anyhow.
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I agree. Break in the engine with some driving around town for a few hundred miles and enjoy the car before racing it. I assume you used molly rings. Just know there quick seating. Change the oil @ 50 miles and go to the track.

daredevil said:
6500 with cast crank and stock rods is where i,d set the rev limiter. is your cam still in powerband that high?
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I have taken an Old 318 that high before. No problems. His cam is to 5800 rpm. But I think power will drop out by 5000 - 5500 area.

MOPARJ; Good cam choice.
 
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