The heads were ported 305 heads with 1.84-1.50 valves.ģ5 total timing 91 octane it was a happy camper. 015' gasket something like 11.9 compression. Overbalance I have heard is a good thing for higher RPM.Īnother engine I built with 57cc chambers was a short rod 385' and the 280H comp magnum flat tappet cam. Say it was zero balanced and you took off 30 grams you would have an over balance situation and i have went with lighter pistons and got the same and Never an issue. If you took some off the tops of those pistons you would not be removing much weight and a rebalance would not be needed in my mind. Roughed up intake runners to promote atomization of the fuel. To make it work all sharp edges on piston top and valve reliefs and on chamber edges were smoothed. Was very happy for 70,000+ miles right up until the pick up screen fell off the tube.ĩ1 octane liked 38-39 total timing depending on weather. It had the comp 270H magnum hydraulic flat tappet. 028' and I ran 186 castings milled to 54cc after porting etc. I ran 11.9 compression in a 350' with cast flat tops but with gasket in place my piston to head was. As a non-stock cam, many Corvette guys run cranes F-278-2 and says it works ALOT better and apparently more friendly to higher compression with non-race gas.Īny compression wizards here give me some advice? Since this is a period motor going into a near NCRS resto - I'm looking one of the old factory GM cams - either the venerable -346 30-30 cam or the more than likely, the -178 LT1 camshaft - both of which are long duration, lower lift, wide LSA camshafts which I know bleed off a ton of compression - but i'm guessing not enough to be safe with 93 octane. This would yield me 12.5:1 but with an aluminum head and probably a much better chamber that might tolerate higher compression - but i don't wanna guess here.

If i shelf the Z28/LT1 heads, i'd consider running the new Trickflow DHC175 heads which look like the old Z28/LT1 heads but are cast aluminum, but are as cast with 60cc chambers. Yields me 11.81 which i think is too high under almost all circumstances to run 91 or 93 octane pump fuel (which is what is regularly available to me) Running the stock 64cc heads - factoring in. TRW 7009p pistons which have an 11cc dome Trying to determine if i can make this combo work.īuilding a period appearing 1970 LT1 engine for my 70 Corvette.īlock is an undecked 350 that will be.

Flycut pistons yourself