Cam Swap Advice

General engine tech -- Drag Racing to Circle Track

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Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

...and had to run on Pump Gas (93 Octane).
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Re: Cam Swap Advice

Post by prairiehotrodder »

I don't see anything really unique about any of that. I'd say give it the cam it wants and enjoy. I used to build my stuff with a lots of compromises then try and reach tough ET goals. It just cost lots of headache. Now my main compromise is just to be basically street legal and pump gas. Get David Vizards BBC book for some good reading. Buy one of the cams suggested by a pro such as Mike Jones or Chris Straub or DV. Every dyno test I've ever seen says EFI makes less power than the right carb but hey if its working good for you keep it. As you stated earlier your not searching for evry 10th of a second at the track.
Brian
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Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

Yeah, I guess that's what most are looking for in a build now that I think about it...there are those that are willing to push to the edge with smaller just to make the same HP/TQ, but sacrifice longevity and reliability. I was hoping to build something so sturdy that GM would warranty if they built it, lol. I'm going to fill out the cam recommendation forms on Jones Cams website...Lunati still hasn't replied yet and I even sent a follow-up e-mail last night. I'm hearing really good things about Jones since first recommended though.

I appreciate all the feedback!
1968 Camaro
Dart Big M 10.2" 572 stroker (4.5 bore x 4.5 stroke)
CR 10.5:1 to 10.75:1
Comp Roller Cam .561/.581, 300/306 (248/254 @ .050), 112 LSA
Dart Pro 1 (Rev 2) as-cast, 345cc, 2.30/1.90
Edelbrock Super Victor EFI
Dougs Full Length 2 1/8"
F-BIRD'88
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Re: Cam Swap Advice

Post by F-BIRD'88 »

You dug your own grave on the cam with your wishy washy requirements.. I bet hyd roller got mentioned on the tech phone too at some point and thats why you got a dummyed down cam... U got what you asked for..


A big 270-280 (.050")duration solid roller cam will not idle in gear at 8" manifolfd vacuum.. Not in gear.

If it is only 10:1 cr don't get all carried away on duration..
260 to 266 deg is plenty. that cam on a 108 lsa will be plenty loppy and go like hell on the street. lift will be .666" .677"

comp xr solid roller lobes #4877 in # 4878 ex. 108 lsa 105 in c/l.

What ever valve springs you got now will likely be Wrong now.
set lash COLD @.010"... comp will advise. They have premimum upgrade spring if you like to rev the hell out of it..
ASK....about valve springs.
Even this cam may not idle at 8" vac in gear.

But it will run hard on the street.
Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

I've made the decision to upgrade my EZ-EFI to the Sportsman unit and stop compromising with vacuum and other requirements, and give the motor what it really wants. As far as digging my own grave, I bought the Solid Roller Lifters, Rockers and Cam all on the same phone call and I assure you, there was no confusion on my part or mention of Hydraulic.
1968 Camaro
Dart Big M 10.2" 572 stroker (4.5 bore x 4.5 stroke)
CR 10.5:1 to 10.75:1
Comp Roller Cam .561/.581, 300/306 (248/254 @ .050), 112 LSA
Dart Pro 1 (Rev 2) as-cast, 345cc, 2.30/1.90
Edelbrock Super Victor EFI
Dougs Full Length 2 1/8"
Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

I pulled the trigger with Chris Straub on a new custom grind Cam he's designed, Morel Lifters and Rockers and received the new FAST XFI Sportsman ECU. Some expressed interest in what recommendations were given: Lunati and Comp Cams never replied to my Cam Recommendation inquiries I sent via their Cam Recommendation Form on their respective websites, and I followed up with each of them at least twice. Mike Jones did respond a little over a week later with the following recommendation; however, it was a little late and after my vacuum requirements changed--i did appreciate the response though and nothing negative to say or imply.

Jones Cam Recommendation
BBC/Cst, R76424-77424-114
256/260 @.050"
.424"/.424" Lobe Lift
.701"/.700" Net Valve Lift, w/1.7 rockers
114 LSA
Steel Billet, w/iron gear
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Re: Cam Swap Advice

Post by prairiehotrodder »

interesting, I bet the straub cam wasn't on a 114 ?
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www.therocketshop.blogspot.com
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Re: Cam Swap Advice

Post by CamKing »

Greenville68 wrote: Mon Feb 19, 2018 9:22 pm Mike Jones did respond a little over a week later
Sorry it took so long. I was out of the country from the 6th to the 11th, and that put me way behind in answering recommendation requests.
Mike Jones
Jones Cam Designs

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jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

No worries...maybe next time.
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Re: Cam Swap Advice

Post by Greenville68 »

prairiehotrodder wrote: Mon Feb 19, 2018 9:29 pm interesting, I bet the straub cam wasn't on a 114 ?
Likely not, as the vacuum requirements were no longer there...he is finalizing the design this week, so I'll share the measurements once I get them.
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Re: Cam Swap Advice

Post by CharlieB53 »

Any bets on LSA from Chris? I've read of many ground on a 108 that do the job just fine. I am hoping to start my build later this year with a few inches on a 108. Just not today.
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Re: Cam Swap Advice

Post by Newold1 »

The EFI system you are running will make a big difference where you take the cam choice LSA. Uunless you want a rough load up type idle at 1200-1300rpms all the time you will have an issue trying to keep that engine idling in a decent manner especially depending on what converter you will be using and how much stop and go driving miles you will be doing. That cam spec is to small for that size engine and desired rpm max and the needs of those heads at those rpms. I would say a 262 intake/272 exhaust @.050" with a 113-114 LSA on a 108 C/L, valve lifts at .650-.680" will get you a 850-900rpm idle tunable on your combo. JMO
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Greenville68
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Re: Cam Swap Advice

Post by Greenville68 »

Here are the final specs for those that held interest:

.705/664
259/273
107LSA
1968 Camaro
Dart Big M 10.2" 572 stroker (4.5 bore x 4.5 stroke)
CR 10.5:1 to 10.75:1
Comp Roller Cam .561/.581, 300/306 (248/254 @ .050), 112 LSA
Dart Pro 1 (Rev 2) as-cast, 345cc, 2.30/1.90
Edelbrock Super Victor EFI
Dougs Full Length 2 1/8"
prairiehotrodder
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Re: Cam Swap Advice

Post by prairiehotrodder »

that will work good. Either of the cams suggested are a big improvement over what you had. Tight lobe sep angles are kind of the new trend as far as I can tell. I've tried a few different cams and found that as long as you aren't way off, there is more to be gained in other places than camshafts. Let us know how it works.
Brian
The Word of God is quick and powerfull
www.therocketshop.blogspot.com
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Re: Cam Swap Advice

Post by Aukai »

What RPM range did you request?
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