Combo suggestions

[Z06killinSBF]

Current combo:

.040 289
Forged TRW's
Isky 262 cam (.445/.445 262/262adv 108*)
Ported E7's w/ adj. 1.6rr's
RPM Air-Gap
600 Edelbrock carb

This combo puts the car in a 13.9 1/4 with 2.80's and a C4. I am in the process of putting a T-5 in it and will eventually put decent gears in it.

The question is that I have a Comp Cams xe-266-hr (.544/.555 216/224 112*) roller cam sitting in my garage that I planned to put into my 5.0. Plans changed. How well would this cam work in my combo? Would I have to worry about valve clearance? I dont know where my compression ratio is with these heads. 64cc vs. 54cc. Any advice. Thanks

 

[Z06killinSBF]

No one?

 

[tylerrocks]

Well, you should always check P-V clearences because timing events (ramp rates) are what will cause problems. That being said I have an F303 with 1.7 RR .544/.544 lift 226/226 @.05 and GT-40p heads with a zero deck and I have over .150 clearence.

 

[SoCalCruising]

You should call Comp and see what they say. You may need a retrofit-type cam with a different base circle, or maybe just using linked roller tappets is okay - I'm not sure as my block is a roller block and I didn't have to look into that. As far as cam specs go, I would think that that cam would be fine. You don't want to use too big of a cam (duration-wise) with 64cc heads or you will loose too much dynamic compression. It would be a good idea to have the heads shaved.

Your springs are likey not optimum for that cam and you must use screw-in studs. P-V clearance should always be checked, but it should be okay if you are using valves that match (or are smaller than) the valve reliefs on your pistons.

 

[57fairlane]

The t-5 and a gear will definetly keep a smile on your face for the next couple of months or so.

But I think, as in any project, you really need to decide your plans. If you don't want to spend too much more and decide you are close to the end of your project, I would get a custom ground cam and mill the heads some (probably end up spending for some new pushrods) and call it a day. You can get a hyd flat tappet from Jay Allen for $140. Would be much better than any OTS cam.

But that XE cam won't work in the block you have unless you get different roller lifters (expensive).

 

[D.Hearne]

I'd guess your comp ratio is way low at around 8 to 1. Less if the pistons have anything less than a zero deck clearance. Increasing the compressed volume by 10cc's is at least good for a 1 full point reduction in the ratio. I don't have my calculator here, but I'll bet I'm not far off on this. Now if those TRW's are the popup's, then disregard this estimate. As for the P/V clearance, I don't think you'd have a problem with the roller.