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08-17-2010, 03:33 PM | #1 |
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Location: Imperial Beach, CA
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HP/RPM gain worth TQ loss?
So in looking for a new cam and RPM's i am debating if it is worth it. Im looking at 2 cams (Lunati 402A3 and A4) which will increase my RPMs to about 6200+ and im thinking about 30-40hp and 30ft/lbs down low untill about 4000 RPM's. Anyone have any input? I know the duration of these two new ones will help my heads a lot. So im thinking i could hit 600 HP and the TQ would stay about the same just move up a little in the RPM's.
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69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build. Last edited by ripdog28; 08-17-2010 at 03:39 PM. |
08-17-2010, 11:35 PM | #2 |
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Re: HP/RPM gain worth TQ loss?
how many rpm are you turning it with the current set up?
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Justin weight 3480 with driver 1.35 60ft 6.13@111mph 1/8 mile 9.80@131mph 1/4 mile 434 small block all motor |
08-17-2010, 11:40 PM | #3 |
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Re: HP/RPM gain worth TQ loss?
Aint nobody gonna touch that.If you want a lunati cam call Bullet Cams,There is no such thing as lunati anymore except the name,Bullet,Ultradyne,thats who made the lunati cams.Just giving a heads up on that product.Call Kirk and he will fix you up with whatever you need,it's about 3 miles from the house,Joe Lunati owns the building where they are ,They were lunati,taylor pistons
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Built chevy tuff! Last edited by Rodms; 08-17-2010 at 11:45 PM. Reason: Add |
08-18-2010, 11:34 AM | #4 |
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Re: HP/RPM gain worth TQ loss?
Current cam has a HP max at 5800 and drops off hard at 6200. The A3 is good until 6800 and the A4 until 7000. I know these will have a Max HP around 6200+ and i do expect the TQ to be down only a few points until about 4000.
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69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build. Last edited by ripdog28; 08-18-2010 at 11:35 AM. |
08-18-2010, 12:00 PM | #5 |
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Location: Duluth, Mn
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Re: HP/RPM gain worth TQ loss?
You still have the 1.75 headers on that thing? If you do I can tell you it would be a better use of funds to put a set of 2" primary headers on this instead. You'll probably pick up 20-30hp and lose minimal torque. On the dyno my buddy's 454 picked up 30 hp just with that header change. Went from 570@6000 to 602hp @ 6000-6200. Peak torque moved up like 200 rpm to 4900 otherwise there was no significant change. His engine has AFR 265 heads and a Comp XR280 solid roller and vic jr. intake ,otherwise it is similar to yours. Hooker Comp 2455HKR headers (2" primary, 3.5" collector) is what we used on his 80 shortbox. Slight modifications (because of raised exh. port on the AFRs) to make them work and the price was only $165 new and they don't drag on the ground in a lowered truck.
If you're going to keep the rpms below 5000 the 1.75" headers are ok on an engine this size but anything more than that and it's gonna choke. Our dyno guy is Jason Line's (NHRA pro stock driver) brother. It was funny because he laughed about us trying the small headers but it ended up being a good learning experience on how much difference a small investment in certain parts can make. Oh, and being you have a flat tappet cam in a bbc it's probably going into valve float as well unless you have a lot of seat pressure on the springs. This is very common.
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85 GMC 1/2 ton LWB 4150lbs. 383 SBC with Twin MPT70 Turbos 850 CSU carb TH375 3.70 gears Ultimate 10" Converter 10.11@136.6 with 1.64 60ft. on 10.5-31-15W Last edited by BADGMC; 08-18-2010 at 12:05 PM. |
08-18-2010, 02:12 PM | #6 |
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Location: Imperial Beach, CA
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Re: HP/RPM gain worth TQ loss?
I did step up to the Hooker 2in/3.5in headers. As for valve float, i will be limiting the RPM with my Malory box to about 6500 so i don't need to worry to much. If it does happen then ill get some different springs. My plan is to gain some power for now and in a year or two when the wife is more relaxed and allows me to spend money ill go roller set up. Spent over $15,000 in the last two years and need to drop another grand in the next month so i need to minimize what i spend but i do want a roller eventually. I figure some 30-40 extra hp is worth the $2-300 for now.
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69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build. |
08-19-2010, 01:27 AM | #7 |
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Location: Maple Valley, WA
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Re: HP/RPM gain worth TQ loss?
I think the 402A8 looks like more what you need. Another thing you might not have is a stud girdle, you will need it. Honestly, if its only a year or so just wait until you can go full roller. Why waste the money now for a new cam when you can put that towards a bigger roller cam later. If you must have more lift now look for a used set of 1.8 rockers it will give a bump in lift and duration.
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08-23-2010, 04:43 PM | #8 |
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Join Date: Aug 2010
Location: Tennessee
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Re: HP/RPM gain worth TQ loss?
"Rodms Re: HP/RPM gain worth TQ loss?
-------------------------------------------------------------------------------- Aint nobody gonna touch that.If you want a lunati cam call Bullet Cams,There is no such thing as lunati anymore except the name,Bullet,Ultradyne,thats who made the lunati cams.Just giving a heads up on that product.Call Kirk and he will fix you up with whatever you need,it's about 3 miles from the house,Joe Lunati owns the building where they are ,They were lunati,taylor pistons " Rodms - Just wanted to make srue that weveryone is aware that Lunati does exist. We separated from Holley almost 3 years ago and are a stand alone LLC now. Our facility is located at 11126 Willow Ridge Dr in Olive Branch. Anyone is welcome to come take a tour if interested. Thanks! |
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