How about another cam reccomendation question???
Thread Starter
Melting Slicks
Joined: Jul 2001
Posts: 2,609
Likes: 12
From: Massapequa Park NY
How about another cam reccomendation question???
I'm rebuilding a 70 454/390. I plan to keep the headlights, wiper door, power brakes intact. Sent some info to both Comp cams & Crane for a recommendation. Told them I want a strong street engine with good vaccum to operate the accessories. Don't plan to race - mostly weekend cruising.
Approx 10:1 compression
stock mildy ported heads casting # 3964290
Stock intake manifold port matched to heads casting # 3955287
Headers - probably sanderson shorties
Dual exhaust w/crossover
1.72:1 Comp cams roller tip rocker arms
Re - jetted original Qjet #7040205
manual trans
3.36:1 rear
Crane reccomended their Max velocity HMV-278-2a
intake 222@ .050 .529" lift
exhaust 234@ .050 .525" lift
lobe separation of 114deg
Comp cams recommended their XE 256 which I thought was a bit small, and you guys agreed on fredfryguy's post earlier. What do you think about Cranes recommendation?? Any other recomendations?
Thanks
Jim
Approx 10:1 compression
stock mildy ported heads casting # 3964290
Stock intake manifold port matched to heads casting # 3955287
Headers - probably sanderson shorties
Dual exhaust w/crossover
1.72:1 Comp cams roller tip rocker arms
Re - jetted original Qjet #7040205
manual trans
3.36:1 rear
Crane reccomended their Max velocity HMV-278-2a
intake 222@ .050 .529" lift
exhaust 234@ .050 .525" lift
lobe separation of 114deg
Comp cams recommended their XE 256 which I thought was a bit small, and you guys agreed on fredfryguy's post earlier. What do you think about Cranes recommendation?? Any other recomendations?
Thanks
Jim
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: How about another cam reccomendation question??? (70BBvert)
Maintaining good idle and cruise economy with a performance cam is done by delaying intake valve open timing, and keeping the other open/close events the same as a max output cam. For instance:
XE274 has 230I @ ILCA of 106, 236E @ ELCA of 114. Probably will give most torque and worst vacuum. Really needs a good full-length header (at least 34") because of the overlap duration.
HMV278 has 222I @ ILCA of 111, 234E @ ELCA of 117. This is quite similar to the XE274 but with 9degrees later IVO. Vacuum and economy will improve.
Fictitious Cam with 214I @ ILCA of 115, 232E @ ELCA of 117. This cam would give best vacuum, but depress the entire torque curve starting at the midrange. Stock cams are sometimes similar to this.
Each of these cams has the same rev range, just different torque. It's difficult to give you a detailed cam recommendation without analyzing the engine. I don't know how they do it over the phone. It takes me an hour or more.
XE274 has 230I @ ILCA of 106, 236E @ ELCA of 114. Probably will give most torque and worst vacuum. Really needs a good full-length header (at least 34") because of the overlap duration.
HMV278 has 222I @ ILCA of 111, 234E @ ELCA of 117. This is quite similar to the XE274 but with 9degrees later IVO. Vacuum and economy will improve.
Fictitious Cam with 214I @ ILCA of 115, 232E @ ELCA of 117. This cam would give best vacuum, but depress the entire torque curve starting at the midrange. Stock cams are sometimes similar to this.
Each of these cams has the same rev range, just different torque. It's difficult to give you a detailed cam recommendation without analyzing the engine. I don't know how they do it over the phone. It takes me an hour or more.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Re: How about another cam reccomendation question??? (70BBvert)
I know you don't want to hear this, but Comp Cams 288R gives me 13-14 inches of vacuum, idles steady at 800 and pulls like a SOB.
Instructor
Joined: Oct 2002
Posts: 171
Likes: 0
From: Southport North Carolina
Re: How about another cam reccomendation question??? (70BBvert)
Hi Jim, I see you have been following my posts! I just talked to my Corvette specialist and he recommends the Comp XE11-242-3, 268 grind (comp Cam rec this cam or the milder 256H) for my stock 454, 4spd. It has great low end power and a nice loping idle. I'm ordering the kit and roller rockers. Probably have the work done in Jan, so they tuned! Good luck, the fryguy :seeya
Safety Car
Joined: Oct 2000
Posts: 4,080
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From: Allen TX
Re: How about another cam reccomendation question??? (GDaina)
I know you don't want to hear this, but Comp Cams 288R gives me 13-14 inches of vacuum, idles steady at 800 and pulls like a SOB.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Re: How about another cam reccomendation question??? (WA 2 FST)
I know you don't want to hear this, but Comp Cams 288R gives me 13-14 inches of vacuum, idles steady at 800 and pulls like a SOB.
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
Safety Car
Joined: Oct 2000
Posts: 4,080
Likes: 565
From: Allen TX
Re: How about another cam reccomendation question??? (GDaina)
Ok, thanks for the clarification based on a real-life experience. That is what is most important.
Does seem a bit odd that it is the same...especially given the head/intake combo didn't change any. I would figure the 533 would be much more docile regarding low-speed driveability. Hmm...interesting.
Does seem a bit odd that it is the same...especially given the head/intake combo didn't change any. I would figure the 533 would be much more docile regarding low-speed driveability. Hmm...interesting.
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Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
Re: How about another cam reccomendation question??? (GDaina)
I know you don't want to hear this, but Comp Cams 288R gives me 13-14 inches of vacuum, idles steady at 800 and pulls like a SOB.
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
You would think, but that is not correct....you see, I had that cam in my 427, and the characteristics are the same, same vacuum, same idle...same heads, same intake, same C.R. only the block, crank, rods, and pistons changed.
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
You would think, but that is not correct....you see, I had that cam in my 427, and the characteristics are the same, same vacuum, same idle...same heads, same intake, same C.R. only the block, crank, rods, and pistons changed.
Race Director
Joined: Feb 1999
Posts: 16,978
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From: In Dreams There Is Truth Ohio
Re: How about another cam reccomendation question??? (Fevre)
I know you don't want to hear this, but Comp Cams 288R gives me 13-14 inches of vacuum, idles steady at 800 and pulls like a SOB.
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
You would think, but that is not correct....you see, I had that cam in my 427, and the characteristics are the same, same vacuum, same idle...same heads, same intake, same C.R. only the block, crank, rods, and pistons changed.
Did you ever dyno it with the 427 and 522? Curious as to if the power range shifted down like you would think it should. :confused:
:D And you also have 100+ more cubic inches...taming the cam significantly. It would act totally different in a 427. :)
You would think, but that is not correct....you see, I had that cam in my 427, and the characteristics are the same, same vacuum, same idle...same heads, same intake, same C.R. only the block, crank, rods, and pistons changed.
Did you ever dyno it with the 427 and 522? Curious as to if the power range shifted down like you would think it should. :confused:
Thread Starter
Melting Slicks
Joined: Jul 2001
Posts: 2,609
Likes: 12
From: Massapequa Park NY
Re: How about another cam reccomendation question??? (GDaina)
WOW - You guys were busy while I was out to lunch :lol:
Some more to think about. Thought I would need at least 16" of vacuum to operate the power brake & accessories.
Jim
Some more to think about. Thought I would need at least 16" of vacuum to operate the power brake & accessories.
Jim
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Re: How about another cam reccomendation question??? (70BBvert)
my 68 doesn't have any power accessories.... :lol: :lol: :lol: ..... except the 533 incher sitting in the engine bay...... :lol: :lol: :lol:
Safety Car
Joined: Aug 2001
Posts: 3,892
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Re: How about another cam reccomendation question??? (GDaina)
The 288 is not a radical cam, even for a 427. I am running a little more aggresive XR280R in a 454 and it is a good street solid roller. I am stepping up to a much more aggresive 300r 255 and 262 at .050 and 652 lift on a 112.
Drifting
Joined: Jul 2001
Posts: 1,418
Likes: 1
Re: How about another cam reccomendation question??? (70BBvert)
Use the Crane cam you posted and really work the combustion chambers to unshroud the exhaust valves along with the intake valve CC walls,,this will increase flow,increase chamber volume and potential detonation with the 114 LCA cam will be reduced.Your Q-Jet will like this cam a bit more as well.
I don't think you will be disappointed- No need for larger valves with this one imo. Porting will still produce a gain,,the chamber work really helps these and it quite easily done
I don't think you will be disappointed- No need for larger valves with this one imo. Porting will still produce a gain,,the chamber work really helps these and it quite easily done
Thread Starter
Melting Slicks
Joined: Jul 2001
Posts: 2,609
Likes: 12
From: Massapequa Park NY
Re: How about another cam reccomendation question??? (mountainmotor)
Thanks guys for all the sugestions. :thumbs: Think I'll stick with the Crane Cam as that was the one my engine shop recommended also.
