Cam choice question, only two so far.
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Joined: Jun 1999
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From: Dove Mountain Arizona
Cam choice question, only two so far.
I've used both of these cams. What I'd like to know is if I would be doing myself a dis-service by using the Summit. The one I have now is the CC's XE274H, and my other choice would be the Summit K1107. I really liked the Summit cam for sound/power but it was a little unhappy cruising under 1500 rpm. My current XE274H has somewhat better at 1500 rpm cruise but I despise the idle quality. It's more 'intense' I guess at idle as opposed to the easy to listen to rumpty-rump of the K1107. My real question is 'in the power band' intensity. What would I be losing/gaining with either?
Comp; duration @ .050 is 230 in. 236 ex... gross lift .487 in. .490 ex. with 110 lobe sep, 106 intake C/L.
Summit K1107; duration @ .050 is .234 in. .244 ex...gross lift .488 in. .510 ex. lobe sep, 114.
The engine I'm now putting together is a 355 sbc, forged 9.7 cr Speed Pro (L2256F30), Sportsman II (64cc) 200cc runner heads, Weiand Stealth and Holly 650 DP, 2.5" rams horns to SuperTurbo's (2.5" all the way out).
Could use some sage advice on these two cams.
Comp; duration @ .050 is 230 in. 236 ex... gross lift .487 in. .490 ex. with 110 lobe sep, 106 intake C/L.
Summit K1107; duration @ .050 is .234 in. .244 ex...gross lift .488 in. .510 ex. lobe sep, 114.
The engine I'm now putting together is a 355 sbc, forged 9.7 cr Speed Pro (L2256F30), Sportsman II (64cc) 200cc runner heads, Weiand Stealth and Holly 650 DP, 2.5" rams horns to SuperTurbo's (2.5" all the way out).
Could use some sage advice on these two cams.
Racer
Joined: Jun 2001
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From: Sanford Florida
Re: Cam choice question, only two so far. (MasterDave)
I think that the cams will be fairly similar, with the summit having maybe 10 or 15 more horse to be around 340-350, and the current cam maybe having 15 more ft/lbs off idle. Depending on the car, gears, tranny and intended driving purpose, I would think you would be happier with the smaller of the cams. As I am sure you know, your biggest restriction is the manifolds. I may even try to find a cam with the duration like the summit, and the LSA like the comp to help clear out the exhaust through the manifolds. Your peak power is probably around 5500, or 5700 rpms depending on the cam, and your torque is probably peaking around 4000, or 4400 depending, again, on the cam. Personally, I would go with the smaller of the two, unless you put headers on it, then the larger might work very well.
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From: Dove Mountain Arizona
Re: Cam choice question, only two so far. (chuckb01)
Thanks Chuckb01, I'm torn btwn these two cams. I know everyone says to use headers, but I really dislike them. My experience with all headers I have ever used is exhaust leaks. Do you really gain that much HP from headers? These old cars ran nicely with 375+ hp from the factory with the 2.5" ramshorns. You say the Summit cam peaks torque at 4400 and the comp at 4000, and the HP moves up 200 rpm? Looks like the power band goes up 200 to 400 rpm's with the Summit over the Comp. Lotsa folks here think torque is the KING and that they would gladly sacrifice rpm's for torque any day. BTW, in looking up true dyno #'s from the World Products website, it shows the combo I'll be using at 430 HP, but they may indeed be counting on headers, dunno though. Hard to believe headers would be worth almost 80 HP... :confused:
Oh, using 3:70 rear, Muncy 4 spd; car is mostly a cruiser but I will go to the T&T day at the drags once in awhile.
Oh, using 3:70 rear, Muncy 4 spd; car is mostly a cruiser but I will go to the T&T day at the drags once in awhile.
Drifting
Joined: Jul 2001
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Re: Cam choice question, only two so far. (MasterDave)
Dave IMO you need a custom cam which utilizes a more agressive exhaust lobe from the Comp master list in an effort to get that thing to go good with the Rams horn manifolds.Not a fix all but will help with what you are working with.I got just the ticket for ya!Not a secret by no means just not interested in all the typing if your not interested in going that route.Email if interested and in turn I will post the specs.
[Modified by mountainmotor, 4:52 PM 4/4/2002]
[Modified by mountainmotor, 4:52 PM 4/4/2002]
Racer
Joined: Jun 2001
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From: Sanford Florida
Re: Cam choice question, only two so far. (MasterDave)
Yes, my estimates are probably pretty conservative, and world products a little overstated, but I think headers could easily be worth 30 or more horse on smallblocks. The 2.5" ramhorns, are good, but manifolds dont match headers. I will get debated over this, but it makes sense to me that torque is really over rated. You will get a better off idle punch with torque, like stop sign to stop sign, but if you think about it, how much time do you really spend in a race below 3000 rpm's? I read a long tech article about that, but cant find it. You should call crower at 1-619-422-1191 for the best reccomendations on the cam. They really know their poopie. Remember also that World does their test with NO accessories, not a water pump or anything (I think), so thier numbers would also reflect that. I am certainly no expert, so don't rely on what I say, but I would look for other cam profiles as well, especially if you are going to use manifolds :cheers:
Melting Slicks
Joined: Aug 1999
Posts: 2,848
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From: Atlanta, Ga, Fulton
Re: Cam choice question, only two so far. (MasterDave)
Hi Dsve
Funny you are talking about cams. I have the XE268 in a 9.6 to 1 350 Ci with Edelbrock heads and an MSD igniootion and I was always wondering about the XE274. I was going to gen up a thread about that and ask what you thought of the XE274. I kinda like the 268. It seems to have good low end driveability a fair idle at 800 RPM and for my purposes it is good up to 6000 RPM.
Cams are kinda subjective. One guy loves a certain grind another hates it. I have a pretty deep first gear with the 3:27 low in the Richmond and a 3:36 rear ratio. I can pull away from a light in 2nd with no problem. Sometimes I shift 1,3,5 and the car runs nice and smooth. Just some food for thought. I also have 2.5 Rams Horns and a 780 Vac Secondary Holley
Funny you are talking about cams. I have the XE268 in a 9.6 to 1 350 Ci with Edelbrock heads and an MSD igniootion and I was always wondering about the XE274. I was going to gen up a thread about that and ask what you thought of the XE274. I kinda like the 268. It seems to have good low end driveability a fair idle at 800 RPM and for my purposes it is good up to 6000 RPM.
Cams are kinda subjective. One guy loves a certain grind another hates it. I have a pretty deep first gear with the 3:27 low in the Richmond and a 3:36 rear ratio. I can pull away from a light in 2nd with no problem. Sometimes I shift 1,3,5 and the car runs nice and smooth. Just some food for thought. I also have 2.5 Rams Horns and a 780 Vac Secondary Holley
Thread Starter
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Joined: Jun 1999
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From: Dove Mountain Arizona
Re: Cam choice question, only two so far. (TheOman)
:D -O-, don't think the mis-spelled words slipped by me unnoticed. You're too funny. Go get some coffee. Anywhoo, I actually like this cam (XE274H), my engine will idle happily at 650-700 but I haven't tried a second gear start. I believe mountainmotor is onto something here. Will letcha know. Hopefully I'm gonna learn something. :cool:
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Thread Starter
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Joined: Jun 1999
Posts: 7,117
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From: Dove Mountain Arizona
Re: Cam choice question, only two so far. (gkull)
Thanks gkull. Also a big thanks to mountainmotor (Curtis). He took his time (and he's not feeling well today) to talk to me at length about my personal preference/needs for camming my engine. The guy has so much knowledge in this field that if you don't have the same base understanding, it makes it difficult to explain it to us 'regular' folks. I wrote some info down, but I'm still absorbing it. Whew! Thanks, I need more education here for sure. Have patience Curtis, I may come over from the 'dark side' yet... :D
Racer
Joined: Dec 2001
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Re: Cam choice question, only two so far. (MasterDave)
Yea, mountain motor (Curtis) has helped me out alot with my choices on engine components. He pointed me away from some stupid ideas (I'm sure he had a good chuckle at a few of them!). I hope to send him some smokey-burnout pics soon (only possible because of his help)!
Racer
Joined: Nov 2000
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From: Hartlepool, England
Re: Cam choice question, only two so far. (MasterDave)
The Summit cam looks almost identical to the Edelbrock Performer RPM I was using except the RPM cam has a slightly tighter LSA at 112* instead of 114* of the summit cam.
I found it to be just streetable and no more and would have been no good as a daily driver. Not much below 2500rpm but would rev hard all the way to 6500+. It sounded great and I still have the original shorty headers. It`s hard to say exactly what the true potential of my combo would have been at the track as I wrecked the clutch trying but even with a close on 3 second 60 foot time I still ran 13.8 in the quarter.
I decided this year to go with a slightly softer cam for some cruising instead of racing. Clutches are to expensive.
SEE & HEAR IT
http://www.smartgroups.com/vault/corvettes/Open%20Pipes
http://www.smartgroups.com/vault/cor...he%20dragstrip
J.
I found it to be just streetable and no more and would have been no good as a daily driver. Not much below 2500rpm but would rev hard all the way to 6500+. It sounded great and I still have the original shorty headers. It`s hard to say exactly what the true potential of my combo would have been at the track as I wrecked the clutch trying but even with a close on 3 second 60 foot time I still ran 13.8 in the quarter.
I decided this year to go with a slightly softer cam for some cruising instead of racing. Clutches are to expensive.
SEE & HEAR IT
http://www.smartgroups.com/vault/corvettes/Open%20Pipes
http://www.smartgroups.com/vault/cor...he%20dragstrip
J.