I was just test fitting my intake/exhaust manifolds on my 1960 235. The front and rear have a guide pin for the exhaust manifold. Has anyone taken these out and replaced with studs to get a better seal after tightening? If so, do they just screw out?
~ John in Utah 1946 1/2Ton w/4-speed manual transmission w/1960 235 engine Here We Go Follow in his DITY Bay
- If you think about it, it has been one year ago today!
The design idea behind using the pins is that the manifold expands in length (mostly front to back) between non-running cold conditions and running hot conditions. Using a bolt on the ends could cause the manifold to warp, creating leaks. I'd stay with the pins.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Replacing those pins with studs/nuts can also lead to cracked manifolds. If the manifold faces are in good shape and even across both intake and exhaust, you should have no problems with sealing when properly installed.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
If the manifold faces are in good shape and even across both intake and exhaust, you should have no problems with sealing when properly installed. 