I bought a 351 roller from a guy that claimed it was a ford factory new long block with only 10K miles. Didnt believe him but the price was right even if it had 100K. It came out of an E350 van. Anyway once I opened it i found no ridge ring and the cross hatch is all still like new, bearings show no sign of wear so heck I guess I got lucky. Heres the issue. I originally wanted (and still do) to build a 393 and put a high lift short duration roller cam in it to put in my early bronco. I have been driving the 302 in the bronco for 5 years and it has never seen 5000 RPM, so pardon me if I dont go wild over heads and intakes and bigger throttle bodies. The 302 is just fine on the highway unless I am heavily loaded and towing. 2500 RPM 2 75 MPH. But it sux offroad. I want LOW END troque and lots of it, but heck the 351 engine is like new and I am trying to compare my actual gains to the money I will be spending throwing away perfectly good parts. I had qassumed it needed a complete rebuild.

So a couple of questions to help me out with my decision. I've seen enough on this site to know that at least some of you understand what I want and wont spout all the high RPM WOT stuff the mustang guys spout even though this engine may not ever even see WOT.

1. what is the combustion chamber volume of the stock 95 truck heads?

2. What are the actual cam specifications I have found varing answers but the prevailing seems to be 256/266 advertised and 204/210 @ 0.05 with .422/.448 lift. I know from experience that a cam with this duration but closer to .5/.5 lift makes for a heck of a torquey engine in the 350 cu.in. range?

3. If I elect to leave the cam and put 1.72 roller rockers on it will I need to change valve springs? I have been told the stock are good to about 0.5" and the 1.72s would get atleast get close to .5", if those cam specs are right.

Basically the original plan was 393, 206/216 cam at .513" lift. and not much else. Since I want to keep CR down near 9 this build is quite expensive by the time all the machine work is done. If all I do is spend money on 1.72s I will still have a much better engine than the 302 with very little in it. Even a cam change would be about the same as the 1.72s as long as I could keep the stock springs and lifters.

Thanks

 

64cc

That's right.

No

Looks like you have a solid platform to build upon there, you will be quite pleased with the increased grunt this motor delivers over a 5.0 just as it is. But don't rule out adding heads and an intake at some point, the stock pieces are WAY too small for this displacement and hurt both HP and torque output.

 

To add to what Conanski posted: if you're going to keep the 95 heads, then at the very least, take the time to remove the Thermactor bumps from the exhaust ports. This takes all of 30-45 minutes (for all eight) with a good carbide bit on a drill. You don't need to disassemble the heads to do it. You can remove the filings with a magnet and wash the rest out using solvent and compressed air. You mentioned throttle bodies and EFI, are you going to run it like that ? Or go carbed ? The F4TE roller works great with a carb, just in case you were wondering.

 

I was going to take out the thermactor bumps as well as do a little port matching, just didnt want to explain why I was willing to do that and not just get new heads.

Well the more i think about it the more i start leaning toward at least dropping in one of these cams w/ 208/216 @ 0.05 and .533/.544. there are a bunch in that size range.

I know I have to change springs, I assume I will have to machine the heads as well. I have never run this kind of lift on a FORD engine.

 

You'll just need to change the springs, if I'm not mistaken. Comp Beehives will do it. That is a hydraulic roller cam you're asking about, isn't it ? As long as you're talking about porting, then I'd open the roof and walls (exhaust ports) to the header gasket size, then bowl blend them all the way. then polish the walls and chambers. I did a set of E7's like this and while I can't give you hard numbers as to the improvement, just looking at em told you they breathed 100% better than before.