How does this cam sound for my 351w??

DarkoStoj · May 3, 2005

First here are the specs on the car/motor

1974 351w block
10.5:1 CR
ported world windsor sr heads
victor jr intake
speed demon 750 dp carb
tremec 3550 trans
4.10 gear

I have a solid flat tappet cam sitting in the garage that I could use. Its specs are 242/251 dur @.50 .617/.639 lift with 1.72 RR's at a 112 lobe separation.

I think the cam would do decent, but I origionally wanted to stick with a cam in the 108* lsa.... but I already have a cam sitting here and that sounds more appealing then buying one. I just wanted to get a second opinion to make sure i'm not severely mismatching parts here.

taylor4g63 · May 3, 2005

Sounds like a pretty good match to me. How high do u plan on spinning the motor?

DarkoStoj · May 3, 2005

probably set the rev limiter at 7k rpm

taylor4g63 · May 3, 2005

Should haul ass. I'm wanting to see a timeslip...

D.Hearne · May 3, 2005

You're gonna be limited to running it on premium gas with that wide LSA. How sure are you about that 10.5 to 1 comp ratio? With the slighly taller 74 decked block and 64 cc heads, you may not have a 10.5 to 1 ratio. Are those the stock replacements for the 69 4 bbl Windsor?

DarkoStoj · May 3, 2005

the heads have been milled to 62cc, and the block has been decked flat with the piston that has 4 2cc valve reliefs. I calculated 10.49:1 compression with running a .039 thick head gasket.

I was hoping to not detonate with 93 octane since I have the WW Sr. iron heads instead of aluminum

D.Hearne · May 3, 2005

If those are Silvolite #1144 pistons, and your block's got a 9.503 deck, your heads are 64cc, head gasket is 9.5 cc, valve reliefs and area around the piston down to the top ring is about 5 cc, your comp ratio is gonna be 8.62 to 1, not 10.5 to 1.

D.Hearne · May 3, 2005

If those are the #1144 pistons, your block would have had to been milled .080 to get a zero deck. That's a LOT of metal to remove.

DarkoStoj · May 3, 2005

the piston is flush with the deck, i believe the pistons are TRW

here is the calc I used to get the compression

D.Hearne · May 3, 2005

I looked up Speed Pro's hypereutectics on their website and with a 62 cc chamber, they give right at a 9 to 1 comp ratio. Comp height for them is 1.772. With a -.030 deck, it works out to 9.65, with a zero deck it's 10.5. If I were you I'd opt for thicker gaskets like the .042" Felpro's, unless you like buying premium gas.

DarkoStoj · May 3, 2005

i was going to run the 1011-2 fel pro head gasket and thats a .039

I do plan on running premium gas also.

DarkoStoj · May 3, 2005

also this is a picture of the piston. It's not at tdc, its just a picture I had of it

bnickel · May 3, 2005

actually with the cam you plan on using you'll need as much compression as you can get. the static compression will be ok but the dynamic compression for this engine with that big of a cam lift and duration and overlap numbers you're cranking compression is going to be very low. another reason to go with a smaller cam

brianj5600 · May 3, 2005

Cast pistons and 7000 rpm's? Better check ptv clearance. I'd be suprised if it will work with stock replacement pistons, shallow valve pockets.

DarkoStoj · May 3, 2005

the pockets are actually pretty deep.

I've checked my engine stats with a couple p2v clearance calculators and both said I should be in the clear.

bnickel · May 3, 2005

DarkoStoj said:
the pockets are actually pretty deep.

I've checked my engine stats with a couple p2v clearance calculators and both said I should be in the clear.

you still need to clay the pistons to be really sure. also there is no way a cast piston will live at 7K. trust em on this i know from experience. i had the exact same pistons in my last motor and i had a prob with my tranny and it sownshifted all the way to first at about 65 mph, hit about 7-7500 for just about a split second. cracked the skirts on 7 of the 8 pistons and the other decide to come apart and took the block with it. i'm not trying to put down your combo or piss you off at all honestly, but i truly think you need to be a little more realistic about this engine. if you use the cam you are planning on and try to rev it 7k with those casr pistons the motor will not last more than 5 passes if that, in fact i think you'll be lucky to get one good pass out of it. also remember the stock 351 crank is really only good for about 5500-6000 rpm. trust me this motor will be nothing but a really big grenade if you stay on the path you're on. might be fun to watch though, if you go through with it make sure you have a friend video taping all of your runs and then post the vids so we can all watch too

How does this cam sound for my 351w??

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