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Sunday, August 19, 2018
  1978 Pontiac Trans Am
 
 

...continued from page 2

How we assembled our torque monster.

After the 2004 season we decided to upgrade from the SD ported 5C heads to a set of the new KRE heads that looked really good on paper. We figured the heads with a slightly hotter cam should give us enough power to break into the 10's. Upon tearing down the engine we found copper in the oil pan. The thrust bearing was almost totally wiped out. We sent the crank to have the thrust surface repaired and at the same time we converted the block to four bolt mains with a set of spare caps we had. The block had already been filled with Hardblock up to the water pump holes and was running TRW forged .040" over pistons with Eagle rods. We reassembled the block running stock bearing clearances on the rods and mains (.001" mains, .0015" rods). The ARP studded mains meant we couldn't use the factory windage tray, so we ordered a crank scraper, Canton windage tray, and Canton road race pan from Spotts Performance.

We ordered a set of KRE 290 cfm heads from Jeff Kauffman and asked him to mill the heads to give us 80 cc chambers (at that time they had only 85 cc chambers in the machined heads). We wanted to have close to 11:1 compression ration with our zero decked block.

We had already decided that we liked the characteristics of the Crane cam we were running with the 5C heads and wanted something similar to work with the KRE heads. However, we were going to go with a solid flat tappet cam in light of our race only combination. Looking through the Comp Cams master lobe catalog, we decided on High Torque solid lobe # 6014 for the intake and exhaust. We would have it ground with 112° LCA to maintain the flat torque curve we were used to. We asked Jeff his opinion on our choice and he concurred but advised a slightly longer duration for the exhaust lobe to pick up a bit more torque. We settled on lobe # 6014 for the intake and lobe # 6016 for the exhaust. We had Jeff order the cam and send it to us along with the heads and a set of Crower solid lifters.

After receiving everything, we went about checking the heads and measuring the cam. The heads looked good and we brought one head to Panaritis Automotive to verify flow numbers. The numbers seemed pretty close to the supplied flow sheet (see flow charts).

When we started measuring the cam however, things weren't as rosy. The duration and valve timing numbers @ .050" were close enough (plus or minus 2°) but the lobe lift figures were lower than the advertised numbers. Instead of .356" intake and .362" exhaust lift we had anywhere from .343" to .353" on all lobes. We called Jeff to ask him his experience with cam number accuracy and he said that's pretty much what you get for flat tappet cams. We degreed the cam, installing it at 108° ICL.

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