Old60Driver
1983 K20 Silverado
- Joined
- May 17, 2020
- Posts
- 245
- Reaction score
- 306
- Location
- Houston
- First Name
- Michael
- Truck Year
- 1983
- Truck Model
- K20 Silverado
- Engine Size
- 350
Howdy y'all!
Recently put a few items into the top end on my (at the time) stock '83 350 with 67K miles. Parts used:
Summit 1103 flat tappet cam
GM performance lifters (3/4 backlash)
PRW 1.5 roller tip rockers
906 vortec heads with screw in studs and beehives, new exhaust valves (intakes were perfect on donor heads, I did lap them and did a drip test with no issues noted) Heads were MT/PTd and checked out good.
Vortec intake
Original push rods. They looked perfect, straight, no burrs or grooves
Lucas SAE 30 break in oil
Already had long tube headers if that matters
Drilled 180 thermostat
Break in went perfectly. No issues at all. No overheating issues at all. Temps have been solid at 180. Been putting around around for a bit, with the occasional thump.
Decided to pull the valve covers and check head bolt torque, and saw a few of the rockers were discolored. Like they got really hot (picture attached)
Started her up with the valve cover off, and all lifters move well, and all the same.
Good oil flow out of the pushrod/lifter after about 15 seconds, she was cold if that matters.
All seems to be okay, except for the discoloration. Haven't pulled the other valve cover yet.
I'm thinking of performing a compression test and leak-down, but any thoughts or advice would be appreciated!
Like I said, she runs fine, a little 'rougher' than before at idle, but I'm guessing it's the cam being just a bit bigger than stock?
Thanks in advance!
Recently put a few items into the top end on my (at the time) stock '83 350 with 67K miles. Parts used:
Summit 1103 flat tappet cam
GM performance lifters (3/4 backlash)
PRW 1.5 roller tip rockers
906 vortec heads with screw in studs and beehives, new exhaust valves (intakes were perfect on donor heads, I did lap them and did a drip test with no issues noted) Heads were MT/PTd and checked out good.
Vortec intake
Original push rods. They looked perfect, straight, no burrs or grooves
Lucas SAE 30 break in oil
Already had long tube headers if that matters
Drilled 180 thermostat
Break in went perfectly. No issues at all. No overheating issues at all. Temps have been solid at 180. Been putting around around for a bit, with the occasional thump.
Decided to pull the valve covers and check head bolt torque, and saw a few of the rockers were discolored. Like they got really hot (picture attached)
Started her up with the valve cover off, and all lifters move well, and all the same.
Good oil flow out of the pushrod/lifter after about 15 seconds, she was cold if that matters.
All seems to be okay, except for the discoloration. Haven't pulled the other valve cover yet.
I'm thinking of performing a compression test and leak-down, but any thoughts or advice would be appreciated!
Like I said, she runs fine, a little 'rougher' than before at idle, but I'm guessing it's the cam being just a bit bigger than stock?
Thanks in advance!
