I'm going to build a smooth idle 427 and drag test it

HP HUNTER · 02-02-2021, 12:16 AM

4.350 X 3.764 447 CUIN, I will use a Racetech piston with a 1.5 1.5 3.0 MM ring pack, compression will be set at 9.7. The center piece of my build will be a copy of a GM 350 HP 396/390 HP 427 hyd cam. My buddy @ Redline will grind it on a original 1960s GM cam core, I will have the LC changed from 115 to112, specs are 460/480/216/218/112, the goal is a dead smooth idle with complete reliability. Spring pressure will be set @ 120/300.
Comp Cams roller tipped rockers will be used with .083 wall moly 3/8 pushrods. I have new 1970s TRW hyd lifters to go on the cam. I used 1971 820 GM oval port heads (only because I had them) honed bronze valve guides, chambers cut on the exhaust side, 1.880/2.190 Ferrea valves installed, fully ported, surfaced and CCs set. For a intake I used a unmodified factory GM cast iron Q-Jet intake of course with a Q-Jet for the carb with a 1inch phenolic spacer. My two carbs were built by Harold Betttes and Vintage muscle car. I used a 402 cast crank with worked over GM rods, everything was balanced. My goal here was to run low 11s in my 68 Chevelle on pump gas with a dead smooth idle, why I have no idea.

02-02-2021, 12:16 AM	#1
HP HUNTER Senior Member Join Date: Feb 2012 Location: Colorado Springs Colorado/Thousand Oaks Ca Posts: 606 Likes: 68 Liked 238 Times in 97 Posts	I'm going to build a smooth idle 427 and drag test it 4.350 X 3.764 447 CUIN, I will use a Racetech piston with a 1.5 1.5 3.0 MM ring pack, compression will be set at 9.7. The center piece of my build will be a copy of a GM 350 HP 396/390 HP 427 hyd cam. My buddy @ Redline will grind it on a original 1960s GM cam core, I will have the LC changed from 115 to112, specs are 460/480/216/218/112, the goal is a dead smooth idle with complete reliability. Spring pressure will be set @ 120/300. Comp Cams roller tipped rockers will be used with .083 wall moly 3/8 pushrods. I have new 1970s TRW hyd lifters to go on the cam. I used 1971 820 GM oval port heads (only because I had them) honed bronze valve guides, chambers cut on the exhaust side, 1.880/2.190 Ferrea valves installed, fully ported, surfaced and CCs set. For a intake I used a unmodified factory GM cast iron Q-Jet intake of course with a Q-Jet for the carb with a 1inch phenolic spacer. My two carbs were built by Harold Betttes and Vintage muscle car. I used a 402 cast crank with worked over GM rods, everything was balanced. My goal here was to run low 11s in my 68 Chevelle on pump gas with a dead smooth idle, why I have no idea. Attached Thumbnails Last edited by HP HUNTER; 02-02-2021 at 12:38 AM.