Slant Six Forum :: Cam for heavy truck?

The cam I put in is Oregom 791 -Intake , 230 @.050, .489 lift
and 1947 - Exhaust, 224 @.050, .470 lift
102 Centerline installed at 100, 106 LSA.

Yes it runs nice. It is not too big at all with the manual transmission. I just drove it again last week. Still will need the 3rd gear on the big hills, but that is what gears are for.

9.77 Compression ratio, 8.5 Dynamic

Jason,
I have driven the truck recently, and while there is no tachometer hooked up and i don't know the torque curve, i'd say it pulls much stronger than stock for the entire RPM range. Its not my truck so I don't run it quite as hard but it pulls strong up to at least 5000 rpm. It pulls very well from 2500 through 5000 at least. I'd guess peak hp is probably around 4800-5000, but it has much more torque through the whole rpm range.

I had oversized valves installed and did have the guides cut down at the same time. Not sure you would have to, but we did anyway.

Author:	Jase [ Wed Aug 08, 2018 11:00 am ]
Post subject:	Re: Cam for heavy truck?
Quote: The cam I put in is Oregom 791 -Intake , 230 @.050, .489 lift and 1947 - Exhaust, 224 @.050, .470 lift 102 Centerline installed at 100, 106 LSA. Yes it runs nice. It is not too big at all with the manual transmission. I just drove it again last week. Still will need the 3rd gear on the big hills, but that is what gears are for. 9.77 Compression ratio, 8.5 Dynamic Thanks Rick, Ok, maybe this is a silly question: would you be willing to estimate in a rough generalization, where the torque curve shows up with that cam, and how far it carries.. And about what RPM the top of the HP curve is reached? jason

Author:	ryandcovalt [ Fri Aug 10, 2018 4:18 am ]
Post subject:	Re: Cam for heavy truck?
Jason, I have driven the truck recently, and while there is no tachometer hooked up and i don't know the torque curve, i'd say it pulls much stronger than stock for the entire RPM range. Its not my truck so I don't run it quite as hard but it pulls strong up to at least 5000 rpm. It pulls very well from 2500 through 5000 at least. I'd guess peak hp is probably around 4800-5000, but it has much more torque through the whole rpm range.

Author:	Rick Covalt [ Fri Aug 10, 2018 5:59 pm ]
Post subject:	Re: Cam for heavy truck?
I did type a post and somehow it disappeared! Ryan kind of covered it !!

Author:	Jase [ Sat Aug 11, 2018 9:13 am ]
Post subject:	Re: Cam for heavy truck?
Quote: Jason, I have driven the truck recently, and while there is no tachometer hooked up and i don't know the torque curve, i'd say it pulls much stronger than stock for the entire RPM range. Its not my truck so I don't run it quite as hard but it pulls strong up to at least 5000 rpm. It pulls very well from 2500 through 5000 at least. I'd guess peak hp is probably around 4800-5000, but it has much more torque through the whole rpm range. Fantastic. That sounds like there is no down side... IF one is going to do a cam swap, and build the engine to suit. Thanks for the reply Ryan, as you have fully answered my question.

Author:	slantsix64 [ Tue Aug 21, 2018 11:16 pm ]
Post subject:	Re: Cam for heavy truck?
Quote: The cam I put in is Oregom 791 -Intake , 230 @.050, .489 lift and 1947 - Exhaust, 224 @.050, .470 lift 102 Centerline installed at 100, 106 LSA. Yes it runs nice. It is not too big at all with the manual transmission. I just drove it again last week. Still will need the 3rd gear on the big hills, but that is what gears are for. 9.77 Compression ratio, 8.5 Dynamic Did you have to trim your valve guides to run 470 lift? 489 lift?

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Author:	Rick Covalt [ Wed Aug 22, 2018 3:08 am ]
Post subject:	Re: Cam for heavy truck?
I had oversized valves installed and did have the guides cut down at the same time. Not sure you would have to, but we did anyway.

Author:	slantsix64 [ Wed Aug 22, 2018 11:19 pm ]
Post subject:	Re: Cam for heavy truck?
Quote: I had oversized valves installed and did have the guides cut down at the same time. Not sure you would have to, but we did anyway. hmm im running .473 lift, but i heard up to .480 lift if pushing it. hopefully it wont be an issue

Author:	Rick Covalt [ Thu Aug 23, 2018 3:06 am ]
Post subject:	Re: Cam for heavy truck?
I think you will have to check. Is the head off? Then it is simple to have them trimmed down a little. If not it may be close.

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