Hi guys, here's the parts I have so far....
360 block 4.060 bore ('71 casting) already blueprinted and ready for assembly
4.125 crank
6.2 rods
zero deck pistons (with 17cc dish)

would like to go hyd roller cam and aluminum heads
also will be some type of efi....

engine will be going into AAR with auto and 3.91's...
car has power brakes
would love to have 500hp/500tq, but realize that might be an optimistic goal, more importantly to be happy on 87 octane E10
send me some thoughts on how to finish this thing up (cam specs, comp ratio, heads, etc)- Thanks!

I'm not sure of the exact specs, but your rods seem a little long for that much stroke..

You must have a 1.33 CD I'm guessing and thats if your deck is exactly 9.600...

I'm not trying to be a smarta$$, just making sure you have the right stuff before you get too in depth in your project...

Also I am just speaking from using diamond pistons. Theirs were 1.45 cd off the shelf IIRC. I used them in a previous build.

Axctually in your case a shorter rod might be less detonation prone if you're hard set on 87 octane.

I'd look at a later magnum style crescent chamber head with about a 1.94" intake, a performer RPM and a vacuum secondary carb tuned a little on the rich side. Hydraulic roller in about the 230/236 @ .050 range. Keep the motor cool as possible, big radiator, big trans cooler independent of the radiator, keep the motor under 180 degrees. It may be tough to find an optimum ignition curve but the 3.91's should help.

I'm thinking hard of converting my little 341 into a high compression but high efficiency motor that should run 12's and still deliver well over 20 mpg using a late model od transmission in an early A body.

yes, pistons have ch of 1.32............

i also agree with the longer rod hurting (as far as detonation resistance), but the rod/stroke ratio is still less than stock...
realistically, how much difference in cam/heads, etc will there be when dedicating the engine up for 87 octane vs 93?

87 oct is gonna be tuff for 500hp(good luck)

I don't think I would be too concerned with trying to get the 500 hp mark,just build the best combination you can to run the 87 octane.The 4.125 stroke and the right head/cam package will make enough torque to twist some axles.
I would work on a nice flat torque curve.

I would not be concerned about running the 92 octane, if you build the motor with the same cam, heads, cubes... but add another point of compression and corespondingly higher octane fuel you will gain some MPG from the increased compression, it makes it very close to the same price to operate the car and you get a little more power to boot. MPG is mostly based on part throttle cruising and higher compression really helps part throttle efficency.

agreed.....it's just a mental thing more than anything.....
i have the same problem with one of my snowmobiles - it's dedicated to run on premium only, and with premium here at $3.70, guess what - it sits. And I want to drive this car, a lot.
I'd much rather give up 50 hp and run el cheapo 87 vs cringing every time i gotta fill the thing up (not that i don't cringe already!)

I suppose it's a personal preference, but to me, the octane rating isn't what's important...it's mileage!

with a difference of .20 per gallon, a 15 gallon fill up is only $3.50 different with regular vs premium.

no matter the price of gas...premium is always .20 higher than regular...at least here in Ohio.

so, $3.50 more per fill-up. if I can't manage that once a week...then I shouldn't be driving any type of toy/fun ride at all, and need a 35+mpg economy car.

now, getting 10 mpg or 15 mpg with that 10 gallons is a huge difference in operating cost!


Good luck on your build though..this sounds neat...500 hp daily driver on 87 octane!