I built this combo with 'fun to drive' and streetability in mind. I wanted very crisp throttle response and alot of torque, which is exactly what is going on here. It works well, even with my car's current 3.08 gears. With the stock mid 80's dished pistons + the small chamber of the 305 heads, I figure its probably around 9:1 or 9.5:1 compression. It runs fine on 92 octane. initial timing is set at 11 btdc.
I followed tips in this old HotRod magazine article and 'chamfered' the edge of the combustion chamber on the 305 heads, shaping them to work with the larger bore of the 350, to eliminate possible pre-ignition hot spots. http://www.hotrod.com/how-to/engine/...-small-blocks/
I read nearly everything I could find on using 305 heads on a 350. It seems the best 305 heads to use are the "HO" heads, which are the -413 castings. These were found on mid 80's TPI engines in IROC camaros and Trans Am, and also on Monte Carlo SS 305 engines. The "HO" 305 heads have 1.84" larger intake valves, whereas the normal 305 heads have 1.7" valves
Would like to hear from anyone else running 305 heads, or any other low-buck combos.
I'm a broke college student, so it was important to keep my $$ investment minimal for this engine. Most parts came from craigslist or the junkyard. Just goes to show that if you scrounge you can put together a stout street combo for not much $$!!
350 short block: $75 craigslist
305 heads: $20 craigslist
headers: $40 craigslist
intake & carb: $50 @ pick n pull
dual exhaust: $40 @ pick n pull
valve covers: $10 @ pick n pull
hi-flow water pump: $50 @ eBay
new parts I had to buy:
dipstick & tube
rings & bearings
180 degree thermostat
accel header plugs
valve stem seals