OK, maybe I need to elaborate a bit so as to let those of you with the info know what I am trying to achieve. I have done alot with "those other types of engines", but never a thing with this cool little 250 Chevy.
My Goal: Gain power without losing driveabilty. Passing power and towing power if I am practical. But, would enjoy surprising the big-exhaust-tipped-loud-muffler-annoying little economy cars built outside the USA, without hesitation.
Application: 1970 Chevy SWB 1/2Ton, 2WD.
Current Steps Taken: Purchased a Clifford Intake, Holley 390 cfm, and headers. Intake has a carburetor heater plate, exhaust heat plumbing located on underside below the carb area, and a 4bbl carb plate to mount the Holley.
Future Plans: Install a 270 deg duration cam with Rhodes lifters. (From what I have read, the Rhodes lifters help resolve vacuum issues, driveability issues when puttering around town) 1.75 Roller Rockers to improve reliability at higher RPMs. (keeping in mind the stud size will have to change to 7/16th and the bosses turned down .400" for the studs to fit. Install dual exhaust. I planned to port the head, but I keep hearing about this "lump" stuff and/or brazening--I have no idea what you guys are taliking about. Now as far as head work, I am game as to the best plan..bigger valve sizes, porting techniques, etc. I understand the concepts...but lack the specific details for a 250 inline.
This a freshly rebuilt (3500 miles) stock engine and must remain driveable except on my three day weekends, in which I can tear down and rebuild. Another note, I have a spare stock 250 head which I can modify, then bolt on over the weekend.
Thanks for your inputs. This is a great forum.
