Brickman,

Thanks for your interest. To be honest I have only second hand verbal information from a shop guy who did a 383 stroker whereas you have seen it so I yield to your statement of ease for the process. I have only rebuilt a MG Midget 1250 cc 4cyl, a 1300/1600 cc VW engine twice and a Pinto 2000 cc OHC in the past (with dabblings on 59-AB flatheads long ago) so the SBC350 is new to me. There are newer 383 kits that may have this all figured out compared to some original tests adapting 400 cranks. I have read several articles on stroking a 350 but I still would like to be sure the rod bolts rotate in the clear and are replaced by stronger bolts. Just for my own interest I would like to know if the 400 harmonic balancer is used, but I have decided to stay with a 350 rather than a 383. Back to more mpg. So far the only person who has agreed with me is Richard/Tech1 and he wants to flirt with very close tolerances between the top of the piston and the bottom of the head. Economicaly, I can't experiment much or waste an engine just for fun so I am having second thoughts. My present thinking is to just wimp out and buy a crate engine from Engine Manufacturers in Charlotte. They have a low end crate engine that comes with a Performer intake and for $50 more you can get the MTC-1 cam from Melling which seems to be a very close approximation to the Edelbrock Performer-plus cam. Thus with only added headers one can get about 280 HP in close approximation to the Edelbrock Performer package. The interesting thing about this engine is that by figuring back and assuming their deck height is 0.025", their 9.1:1 C.R. must be achieved with a Felpro 0.015" head gasket. This is close to what Techinspector1 wants (he wants 0.035" squish) in that the 0.025" and the 0.015" yields 0.040" squish and a 9.1 C.R. Alas that engine uses the smaller valves with 76 cc chambers and the C.R. is a lot lower than Tech1 expects. At this point I could envision changing the cam to the XE250 and in part achieve the short-cam-high-compression model. For me that is the safer thing to do in that if the experiment fails I can still run on 92 or maybe even 89 octane gas and the extra 0.005" in the squish makes me feel safer that I will not smash a piston. I will still have the 461 double-hump heads and maybe later I can go for 10:1 or more. In case anyone wants to try it here are the two setups:

1. The Risky Experiment

a. 461 SBC 58 cc heads with flat top pistons (7 cc for eyebrows) to yield well over 10:1 C.R.

b. Comp Cams XE-250 short duration cam (I=250, X=260)

c. Thin head gasket to keep squish small (0.035"), block decked to only 0.007" with Chevy part no. 10105117, 0.028" compressed as suggested by Techinspector1 (total squish =0.035").

d. extra care in smoothing out cylinder walls and other potential hot spots to hopefully eliminate detonation. Tech1 suggests zero-gap rings but you would have to leave some gap for thermal expansion.

TechInspector1 hopes for up to 25 mpg!!!!!!!!

2. The Safe Experiment

a. 883 smog heads with 76 cc chamber (Dart heads as in the Comp Cams test would obviously be better); anticipate C.R. is only about 9.1:1, ie closer to the value used in the Comp Cam 250 test which was 9.25:1.

b. Comp Cams XE-250 short duration cam

c. Felpro head gasket (0.015" compressed) with 0.025" deck height to give a safer 0.040" total squish.

d. smooth the cylinder walls with a fine hone to try to remove hot spot detonation.

My "safe" economic thinking is that if I go with the 9.1 CR crate motor and the Comp Cam-XE250, I could at some future point buy the Dart Heads and then be more sure of reaching the results of the test shown in:

http://www.compcams.com/Technical/Dy...50H-10_001.asp

Well you did ask! Another potential problem is that the XE-250 is a pretty violent cam so pinning or threading the rocker studs would seem to be necessary. Anyway Techinspector1 agrees that a short duration cam should lead to better mileage and the XE-250 test shows that low rpm torque is very good without sacrificing much high rpm power, that is contrary to most knee-jerk thinking and maybe Comp Cams will sell a lot of these cams as gas gets even more expensive. The idea that you can still use very high compression (the real secret to power) with a short duration cam by using this tight squish is certainly not safe for worn engines IMHO, but I would like to study this more before reducing the squish to 0.035" or raising the CR to 11:1, BUT I am still pondering this. All of this assumes a tall rear gear and that is also backward thinking, BUT again what are the alternatives? By the way our cheapest regular here in suburban VA is now $189.9/gal with high test at $209.9, maybe "we" need to scratch our heads a bit and come up with something new! I would certainly welcome a more complete essay on this problem from TechInspector1 at his liesure. As I said in another thread my "Golden parachute" at retirement is really a "Copper parachute" and I want to end up with something that runs well and if all I get is 18 mpg on the Interstate that will have to be what it is, but 22 mpg would really be a breakthrough if the engine can still produce over 300 HP on occasion! I am new to this forum but I greatly appreciate the collected expertise available here. I will ponder this more but for now I have to sort out the TCI 4-bar rear kit I got today for my 8" 2.79 rear. Maybe TechInspector1 could figure out how "we" could do this with standard parts like the commercially available XE-250?

Best Wishes,
Don Shillady