Finally, if this is going to be a street/strip toy, check with Hotchkis Suspension for upgrade components, like the Sport Coil front and rear coil spring set, PN 1902. To keep the front and rear of the car where you point it, pick up the Sport Swap Bar set under PN 2201. This will give you a very nice-handling street car with decent strip performance.
Double-Hump MembersQ Are there early-model Chevelle double-hump crossmembers that will fit my '77 Malibu with a TH350 trans? I located a Muncie four-speed crossmember through eBay, but will the TH350 bolt up to this? My crossmember is 5331/44 inches bolt hole to bolt hole.Johnathan Lacy
A Getting a dual-exhaust past '75-and-later single-hump crossmembers can be a challenge, but you're in luck. With the redesign of the A-body cars in '73, the frames are common from '73 through '77. If you locate a trans crossmember from a '73 or '74 Chevelle, it will be a double-hump design. These cars were equipped with either small-blocks or an LS4 454. They had either three- or four-speed manual gearboxes, or a TH350 behind the small-blocks, and a TH400 behind the big-block. They all used the same crossmember, PN 331893-and yes, that crossmember was discontinued back in October 1987. Remember to stick with the Chevelle when looking for a crossmember. The El Caminos had a fully boxed frame and the crossmember is El Camino specific. Either keep digging through salvage yards or scouring the Internet for the crossmember. You shouldn't have much problem finding one out there. GM built tons of A-body cars over those two years.
Back In The DayQ My brother-in-law and I are looking to build 427s for his '68 Camaro and my '66 El Camino. We're not overly concerned with low-end and want high-winding engines. How much horsepower and rpm will a steel GM crank handle? For now, we're looking into using the 6223 casting forged crank. Is the 7115 crank that much better?Paul Schaller
A These types of questions always get me into trouble. I've used both of these cranks over the years and have had good luck with both. Let's first look at the differences in the cranks.
The number 6223 is a forged 1053-alloy steel crank, PN 3963523. This is the standard pedestrian forged-steel crank. Also, I've been told that the 1053 alloy steel is just a step up from cast steel. The 7115 crank (PN 3963524) is forged from 5140 steel alloy, then Nitrided, and cross-drilled. Nitriding is a surface-hardening treatment that hardens the first several thousands of material and is a very good upgrade for a crankshaft. Now for cross-drilling. Back in the day it was the trick of the week. Cross-drilling refers to drilling across the main journal of the crank, which would allow the rod journal to be fed with oil pressure 360 degrees of crankshaft rotation. This sounds great until we come to present day. It's not uncommon to see a big-block Chevy rev into the 8,000-rpm range and above. When the engine speed reaches these levels, centrifugal force takes over in the oil gallery and prevents the oil from reaching the rod bearings. That's not good!
I've run cross-drilled big-blocks to 7,000 rpm with no problem. Granted, this is in a drag-racing application; continuous engine speeds in this range may become a problem. Point being, standard oiling is the hot ticket for high-engine speed operation.
The 5140 crank will support 750 hp with relative ease. I have over 11 years on one of my 502s that produces just shy of 700 hp with the 1053 crank. If these are street toys that you and your brother-in-law are building, the 1053 should be fine.