groho

OK, after many years my 66 coupe is finally in paint. While the car is in the shop I have the space to refresh the motor. The subframe and front torque boxes are in so power and cornering is not an issue. Noticed the motor is a '68 302. Since I have to pull the heads and pan anyway, I can ID the crank to determine my next step. I'm trying to put together a head/cam combo without going overboard using the bigger IS NOT better rule. This will be a fun car to take to autocross events, drive, and come back home, maybe with a few runs on the 1/4 mile, and milk runs for my understanding wife. It needs to be managable in stop and go traffic. If its a 302, I plan for afr185 heads, a 289 would get afr165 heads. I want to achieve 6500 consistantly, without worry. The tranny is a built C4, with rigid bands, C-servo, extra clutches and soon 2500 stall T/C. I'm thinking a 510 lift, 225 dur, with 110 overlap would be about right. I see a roller conversion is not complicated using the Compcams 31-1000 kit, but how many of you have drilled/tapped your own blocks without damaging cam bearings? Should it be done by a machine shop? I don't know didley about roller cams, and could really use some feedback. How are they at 6500 RPM? Thanks for the feedback in advance.

racer_dave

I've never drilled/tapped on an assembled engine, they were always apart. how many miles on the engine? What do the bearings look like? If its out, I'd check it all out. at this point its only a bit of money to put new bearings in it and do the small bit of work to it to go roller. As for a cam, I gave up spec-ing my own years ago. I call Comp Cams, tell them all the particulars(c.i, crank, pistons, heads, exhaust, intake, car weight, gearing, referred rpm band, trans, driving style etc...) and have them give me a few options.

groho

Good news, the motor is a '68 302, with 302 crank and valve relief pistons. I'm thinking a 9.7 compression. Bored .30 over, with a .10/.10 crank. We couldn't find anything wrong, and looked like the motor was rebuilt in the last year or so of use. No scoring in the cylinders, and no ridge at the top of the cylinder. In fact the cross hatching were still very visible. Pulled one main and one rod cap, the bearings look fine, min ware with no brass or burning. The cam bearings look good also. The cam that was used appears to became remanufactured cam. I'm gonna keep this simple, and cheap, 165 renegade heads, solid lifter cam, reuse my weiand intake and carb. I don't see anything that warrants spending money for a rebuild or stroker kit.

racer_dave

sounds like a smart plan.

kenash

Hi,
I have done the drilling and tapping required to add the spyder assy for roller conversion. It's a very tedious operation and can be done with simply exposing the valley pan area, but, it's not for the faint hearted. The easiest, is to go with the link bars. I, eventually, upgraded to these in my second build. However, they are more "spendy". Obviously. to complete the package you'll want to add the roller rockers, as well. You say, you want to achieve "6500 consistently without worry", you will need to think in terms of a custom billet cam, and numerous "forged" balanced rotating components and blue-print assembly. The 185 AFRs are nice heads, but, will need the rest of a "total package' to realize their potential. I've walked down this road, so, I speak from experience.
Good Luck with your project.

groho

OK, making progress. After looking at my objectives, I softened the cam, choosing the CompCams XE268 with AFR165 heads. The Canton pan and pump showed up this week, and I expect to order the cam, heads, rockers in the next couple of days. Just ordered the custom torque converter yesterday, 2400 stall, hardened spline hub (4130). Things are coming along. I have to keep reminding myself to build a package that works together. I think this will do it.

kenash

I think your head a cam choices are excellent combo. Is this a nice street warrior?
What header system? Will it be a roller?

barnett468

you need at least 3.43 gears with that set up or it will feel like a pig.

you need the 58 cc heads then deck your block to .005" piston to block height, then mill those heads .028" to opti,ize your perf with that set up on 91 - 93 octane or E85 corn gas.
.

kenash

Yeah..."Barnett468" offers a some much needed advice. The truth is, you're gonna have to lower 'dem rear gears to a 3.55, then "do the math" and machine work to obtain a minimum of 9.5 CR. Please know, to get there, you'll need to mill the head,(58cc, is a good start, as noted) "zero" deck the block to pistons, determine the correct "compressed" head gasket needed, this, together with CC'g. the chambers the piston tops, then adding approx. 2 ccs for ring land area...you'll arrive at your true "static" CR. , Note, I stated "static". Static is what we all brag about without really knowing "in some cases" when hanging on the corner (well, I did 50 years ago) . True (dynamic) CR is determined by factoring in your cam events. This can be a point less than static. Cam events can bleed off pressure resulting in a lower actual CR when the the engine is in operation. This is all well documented. In the end, instead of guessing, you'll really know! As an example, my calculated CR is 10.56. My actual is approximately 9.6 CR due to overlap (opening/closing) of my cam events. This is why I can run some hellatious initial and total numbers without pre-ignition.
Also know, Aluminum heads, by nature, will run cooler, all else being OK. This, together with the right configuration will allow for more initial timing, thus better " snappy" performance. Happy Trails....
Just my point of view.....

barnett468

yes, good info. you can also sneak in another .5 compression using aluminum heads.