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Summit 6401 Cam Timing

69L48Z27

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Been reading a lot of threads on the 6401 Summit cam and I think that’s the way I’ll go. Engine is a bone stock 67 440hp with manifolds, stock carb, 323s and stock converter.

My question is about degreeing the cam. Should this be installed straight up or would some advance or retard help it?

@lewtot184 - you seem to be a big fan of this cam for the application. Let me know what you (and others) think.

Thank you!
 
Did mine straight up. 1967 440 9.3 1 .050 in the hole. Iron 452s, Dougs, Stock converter, 3.23 gear.
 
Mine is also straight up. 75 440 RV block 9.64:1 .005 below deck same heads as Khryslerkid. My timing is set at 14 initial 36 total, but then again its still on the run stand that timing will change once there is a load on the engine.
 
Just be careful if your compression ratio is above say 9.5 with iron heads that cam gives pretty high cylinder pressure. After you run it and get some carbon build up it may start to predetonate or ping. They idle smooth and have a nice broad powerband.
 
Just be careful if your compression ratio is above say 9.5 with iron heads that cam gives pretty high cylinder pressure. After you run it and get some carbon build up it may start to predetonate or ping. They idle smooth and have a nice broad powerband.

With my 9.3:1 I'm getting a 165 lb compression. Weird thing is I've never had pinging even as high as 18 deg timing. It likes 16 with 34 all in. I still need to limit my vacuum advance.

From 2,000 rpm it really makes the power. Stock converter and 3.23s you can hear it kick in in this video...


Smooth idle but you know it's not stock...
 
Nice. The one I was referring to was 205-215 lbs. There was nothing you could do to stop it from pinging. But for a short while it was a beast.
 
I just purchased this cam for a 440 build. Wanted a well mannered street motor with some punch. Nice quality piece! I heard Summit cams are manufactured by Comp, can anyone confirm that? 440'
 
Thanks everyone! This is a 67 with 915 heads. I didn’t check but isn’t this setup closer to 10.5:1 CR.

With that in play, would advancing or retarding the cam change the dynamic CR?
 
Do you know all of the specs of the engine? Has it been rebuilt? Chamber size? head gasket thickness etc etc. Lots of variables there. But assuming its stock 67 440 here are the specs for a 1967 440.
Engine/Disp. Carburator Bore/Stroke Compression Ratio Horsepower @ RPM Torque @ RPM Normal Oil Pressure
V8- 440 4-bbl 4.32 x 3.75 10.1:1 350 @ 4400 480 @ 2800 45-65
V8- 440 4-bbl 4.32 x 3.75 10.1:1 375 @ 4600 480 @ 3200 45-65
 
My engine guy recommended this cam says it works very well with the 440 he says he installs them in a lot of the 440's he builds.
 
Do you know all of the specs of the engine? Has it been rebuilt? Chamber size? head gasket thickness etc etc. Lots of variables there. But assuming its stock 67 440 here are the specs for a 1967 440.
Engine/Disp. Carburator Bore/Stroke Compression Ratio Horsepower @ RPM Torque @ RPM Normal Oil Pressure
V8- 440 4-bbl 4.32 x 3.75 10.1:1 350 @ 4400 480 @ 2800 45-65
V8- 440 4-bbl 4.32 x 3.75 10.1:1 375 @ 4600 480 @ 3200 45-65
Know the specs? Yes but not exactly. Engine has been rebuilt by me but I was the first into the engine. 915 heads with a fly cut to make sure they’re straight, nothing off the block deck. Head gaskets are out of the FelPro gasket set. Cylinders are not cut, we were able to hone and be in spec. Pistons are the born with ones. For the most this is as ‘stock’ as it gets.

Thx!
 
You might check that felpro set to see what the crush is on that head gasket to help you calculate the true CR. It also helps to know your chamber volume. I'm sure you know all of this. I learned as I went. My 440 was my first engine build so I learned how to figure it out. I had fun doing my engine..
 
My 440's CR is 9.28/1. Initial timing is 20 degrees. The 114 degree lobe seperation angle should reduce cylinder pressure compared to the same cam with a tighter lobe seperation angle, one of the reasons I like this cam.The 114 broadens the power curve, I think that's why people like it on stock or tightish converters. With a stock converter it is a bit of a dog down low though it's ok. I think a 2500rpm converter would make a big difference, or rhoades lifters with the stock or tight converter, if you CR is not to high, and you don't mind the sound.

My k6401 is installed straight up with rhoades lifters, 7lbs of boost, street car. I recall someone here mentioning that they tested the cam on a dyno straight up, advanced, and retarded, and the result was keep the cam straight. Cant remember who but the thread is here somewhere.
 
Earlier this week I placed the order for this cam and today it’s installed.

The cam card has the intake centerline at 109, I degree it at 106.5 ‘straight up’. I decided to leave it alone since the advance should help bottom end.

For those who installed and degree the cam, did you experience the same thing? And, does this cam have a couple degrees of advance built in?

I had to use a small degree wheel so my .5 degree may not be anything. I’ll finish getting the car together tomorrow and hopefully have a good break in.
 
Likely the timing set.
Should be fine, better to be advanced.
 
I have on in my 68 Valiant straight up 440 with 323s in the butt 727 at 9.3-1 and it just goes. I got about the same results on the degree wheel as you did.
 
Thx!

Cam is installed and broke in. Not too much drama other than I had one of the valve cover gaskets screwed up, it rolled into the engine so I had a nice leak. That all fixed and ready for first drive.

I have the base timing set at 12 before, I’ll start there.
 
With my 9.3:1 I'm getting a 165 lb compression. Weird thing is I've never had pinging even as high as 18 deg timing. It likes 16 with 34 all in. I still need to limit my vacuum advance.

From 2,000 rpm it really makes the power. Stock converter and 3.23s you can hear it kick in in this video...


Smooth idle but you know it's not stock...

Always wanted to know what your avatar sounded like!
 
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