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| cam question of the week https://slantsix.org/forum/viewtopic.php?t=47342 |
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| Author: | akbmotorsports [ Tue Dec 20, 2011 6:11 pm ] |
| Post subject: | cam question of the week |
hello. i would like your opinions on installing Oregon Cam grind 1475. here is the chart - http://slantsix.org/forum/viewtopic.php ... les#191616 1984 D100 shortbed, use as daily driver with some performance, infrequent light hauling. 904 w/raised stall - 3.55 rear. long rod 225 - stock 198 rods/wiseco pistons. engnbldr valves/guides/springs. hooker 6/1 truck header. offy intake with edelbrock 1404 (500 cfm) carb. thanks, Andy. |
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| Author: | Joshie225 [ Tue Dec 20, 2011 6:55 pm ] |
| Post subject: | |
That's a lot of duration for a heavy vehicle like a truck. If the compression and stall are high enough I'd lean toward (yes, I realize the pun) a 791 intake lobe and a 1416 exhaust lobe on 108° centerline and installed with at 101° intake centerline. |
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| Author: | ceej [ Tue Dec 20, 2011 9:15 pm ] |
| Post subject: | |
That's a mechanical profile. Does your truck have a mechanical valve train? CJ |
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| Author: | Dart270 [ Wed Dec 21, 2011 5:28 am ] |
| Post subject: | |
That is maybe a bit big, depending on stall speed and compression. I would not run it below 9.5:1 static comp and 2600 RPM stall. The #346 looks very good, and I will be using one of those soon (inst at 100 deg CL) with a 9.3:1 mill. Lou |
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| Author: | akbmotorsports [ Fri Dec 23, 2011 6:57 am ] |
| Post subject: | |
sorry it took so long to respond, been crazy around here. Joshua, have you used that combination? i am curious why the difference in lift is beneficial. try to dumb it up for me.  Ceej, i am using the engine from my dearly departed 67 D100, 3 plug forged crank with large register. Lou, that one has my interest, what do you think the power band would be? i want to be able to wind it up a bit when "necessary" i am aiming for 9.75-1 SCR and could maybe go with 3.73 rear gear. thanks, andy. |
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| Author: | DadTruck [ Fri Dec 23, 2011 9:16 am ] |
| Post subject: | |
Andy I sent my cam to Oregon Cam Grinding on Dec 9th , got a call back yesterday, the 22nd that it is getting shipped back to IN. cost was 75.00 + shipping to and fro,, I shipped mine out on UPS,, packed it in a piece of PVC pipe,, cost 21.43 the grind that I am using is a lot less duration than you have selected, but a narrower LSA. I am looking for low RPM torque, yours appears to be a a lot more up the band. would like to make a run at you on the 1/4,, post on your progress regards DT |
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| Author: | akbmotorsports [ Fri Dec 23, 2011 9:43 am ] |
| Post subject: | beauty vs the beast |
DT, that would be beauty vs the beast for sure. (yours being the beauty) i have never drag raced before, but would like to make a couple runs just for fun and see how fast, or slow, the truck will go. would be interesting, yours with duals and small cam, mine with single and bigger cam. got the block and crank back, waiting on pistons to be installed on rods. the head is getting done, started with 60cc chambers and the machinist said i will lose a little volume with the bigger valves but with some unshrouding should be about the same. i will see what they actually measure when i get it back. so if i did the did the calculation right, with 58cc i should be about 9.75. have a great day, andy. |
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| Author: | Doc [ Fri Dec 23, 2011 10:17 am ] |
| Post subject: | |
Ask the cam grinder to give you the estimated Intake Closing point for any grind you are looking at. With the I.C. number, you can get a good look at the DCR. Based on your 9.75 static CR estimate, a cam with a 60 to 65 ABDC Intake Closing event will be a good choice. DD |
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| Author: | DadTruck [ Fri Dec 23, 2011 12:24 pm ] |
| Post subject: | |
Andy my 83 head with stock valves measured 58 to 57 cc's, with the enginebuilder os valves it went to 56 to 57cc's I am only taking my bores .030 over, but de shrouding to that size and with general combustion chamber clean up the chambers on the 83 head are back to 58cc's so it sounds like concerning combustion chamber size you are on track. my guess is with the wisco pistons and 198 rods you are not doing any block or head milling,, is that right? regards DT |
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| Author: | akbmotorsports [ Mon Jan 16, 2012 6:45 pm ] |
| Post subject: | |
DT, picked up the last of my parts from the shop last weekend. they took .010 off the head, ended up right back at 60cc so good there. i will have to see where the piston deck height ends up when installed to know exact numbers. i am going with Lou's cam recommendation, ordered the #346 grind. thanks for the replies fellas. just a couple more items to gather (oil pump, timing set and a few gaskets) and time to reassemble. andy. |
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