Wondering if I overbuilt my last motor. Was intended to be a street/strip car and now is entirely a street car. Its a 67 Chevelle with a 383/4 speed/3:55 rear gear. Was going to be a 4:10 rear gear, but changed it to a 3:55 when it became a street car. We are running 15 x 7 with 235 60's on the front and 15 x 8 with 255 60's on the rear.
The bottom end is good until about 500 horse. It has a cast Eagle crank with something like SIR rods I think with -12 dished hyper pistons in it. Compression came out around 10 to 1, maybe a slush under it at 9:9 to 1. It has 195 cranking compression. The cam is very mild...its a UDHarold design at 280/288 and 226/234 @ .050 with .536/.536 lift on a set of 1.52 roller rockers. The cam is installed at 109 ICL and is on a 112 lsa. Not sure why the builder chose that as the cam card called for 106 ICL. The heads is where I think its overbuilt...for the street...we had a set 200 Dart Conquest ported and flow very well for what they are....they flow at .500 270 and at .600 they flow 285. We used a second hand Edelbrock RPM intake with a Holley 3310 on it. Motor runs fine with the exception of a rocker getting loose from time to time. Our timing is at 18* initial with a 16* mechanical curve for a total all in of 34* around 2100. The can adds another 12* for a total of 48* at cruise.
The car has a 160 thermostat in it here in Florida and runs about 180 to 190 in the Florida summer heat. Fans come on to keep it in this this area, but then go off. Really pleased with the cooling.
I feel the cam would run better on a 108 lsa there is no doubt about that, but I also feel that we should of left the heads alone and run them unported and run a 2.05 valve for the street to keep up velocity. However, Eric Weingartner did the work on them thinking it would be a strip/strip motor. The motor is a little sluggish to me down low for a mild cam, but really seems to run really well at above 3000 to 6500. Seems to pull very nice up there. We want more bottom end with a shift point of around 5800 to 6000 to make it more like a strong street motor....but its all good in that it runs good for a cruiser.
Anyone want to add there opinions to the discussion?
67 chevelle malibu / SS/ custom
Currently undergoing a metal work to remove all rust, if I ever get there.
Cant decide on prostreet or cruiser with a 4 speed.