Ok thank you, ya mine is a 2 bbl engine and I just found it strange that it had the 915's as I read they were a 440 HP head but that makes sense The car has sat for a long time sure hope I can save the original engine... Hoping to just put a 4 bbl, cam and dual exhaust to wake it up a bit, thanks
Going to have to dig into this deeper seems to me with the pistons I have i would lose compression, I am thinking they may need replaces anyways. I wonder if I went to the higher compression pistons and opened up the exhaust waves how it would perform? Also I was wondering about hardened valve seats to accommodate for today's fuel?Ive seen a few 915s whit the small valve. just open the seat and wala.....hp 915s
hello, after measuring the exhaust valves (yes 1.60) and doing a little more research I am quite confident this engine did come with the 915 casting numbers. To me it seems like there was actually 3 possibilities, the 516,158, and 915. The 516's for the 383, the 158's for 440 both with 1.60 valves, and supposably the 915 for the 440 hp but like was mentioned these are truly 915's with 1.60 exhaust valves... I am also very confident this is the original motor, the block was cast in 66 which is normal for a 67 the build date on the car was Jan 20 1967 and the digits are 120. I have one more question, can someone help me decode this block stamp? I know c383 is a 1967 install date but I am a bit confused to the exact date and more confused by the R, I just want to confirm this is the original motor and I thank you very much for the help...View attachment 1033277
I agree with everything but the last sentence. I feel a better breathing engine is more efficient. My opinion would be to build it to 9.7-10.0 compression, and if you are planning hardened seats, go ahead with at least the 1.81 exhaust. My preference would be 2.14 intake/1.81 exhaust and just clean up the intake and exhaust ports, not necessarily port them.C383 means it’s a 67 383
12 2 is December 2nd 1966
2 is second shift
R is for regular fuel so it’s a 2bbl engine.
this is stamped in so 12 2 is the assembly date.
you can never prove that this is the original engine. But the date are in order.
We would need to know your intended use of the car and all the mods you wil be making before we can say to increase the valve size. 1.60 is great for a small cam and stock intake and exhaust manifolds.
1.81 is way to big unless it’s a race engine. IMO