Too Much Cam?
Thread Starter
Instructor
Joined: Aug 2005
Posts: 183
Likes: 1
Too Much Cam?
Hi all,
We have a customer who wants his 77 vette completely restored. He is buying his own engine parts and we are to build the stock bottom 4 bolt 350 motor for him as well as do the interior, body and paint, etc.
He called up Summit and ordered a Holley StreetMax head kit with manifold, 750 Streetmax carb, and Lunati 490/240 cam.
I am concerned this is too much cam for a street driver, since the power range is 3000-6500 RPM. The car has A/C, Cruise control, etc., which he wants to keep. I want the guy to be satisfied with his ride.
I spoke with him about the cam and he agrees that it is bit more than he wanted, but that this is what Holley dyno matched the heads with. I called Summit and talked to a semi-snotty customer service rep, who became increasingly frustrated at my concern about the cam. He said that Holley guarantees that this is a streetable system and that we would have to re-order everything separately if we want a milder cam (something that I think he did not want to do, since this had already been ordered).
Any thoughts? Will the customer be happy with this setup as-is? Why or why not?
We have a customer who wants his 77 vette completely restored. He is buying his own engine parts and we are to build the stock bottom 4 bolt 350 motor for him as well as do the interior, body and paint, etc.
He called up Summit and ordered a Holley StreetMax head kit with manifold, 750 Streetmax carb, and Lunati 490/240 cam.
I am concerned this is too much cam for a street driver, since the power range is 3000-6500 RPM. The car has A/C, Cruise control, etc., which he wants to keep. I want the guy to be satisfied with his ride.
I spoke with him about the cam and he agrees that it is bit more than he wanted, but that this is what Holley dyno matched the heads with. I called Summit and talked to a semi-snotty customer service rep, who became increasingly frustrated at my concern about the cam. He said that Holley guarantees that this is a streetable system and that we would have to re-order everything separately if we want a milder cam (something that I think he did not want to do, since this had already been ordered).
Any thoughts? Will the customer be happy with this setup as-is? Why or why not?
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
A cam with 240 duration at .050" is a big cam... that's in the 310-range advertised duration. It will need headers, a good free flowing dual exhaust, and a 4-speed tranny. He'll also need some gears in the back end, because a '77 A/C car is going to have about a 3.07 rear gear ratio. He's going to need 3:90's to support a cam like that. If it's an automatic, he'll need a good high-stall converter. The car is going to be balky to drive, and it'll be dead at low rpm. I would be very hesitant to install a cam like that in a customer car unless the customer really understands what he's getting himself into....
Thread Starter
Instructor
Joined: Aug 2005
Posts: 183
Likes: 1
My thoughts exactly. He has already ordered a stall convertor for it, though I am not sure which one. He is going to use Hooker side mounts. I find it amazing that this can be called a "street cam" by anyone. My "b" Bracket car had less cam than that! I am tninking that if he saved several hundred on the kit by accepting that cam it might make sense to order a cam only from Comp that runs in the 280 advertized range. It will definitely still kick him in the pants in that Vette with that carb and those heads.
How I usually recommend building a street engine is to use a 10:1 (at the most) forged piston, port the stock 202 heads, get a 280 series cam, roller rockers, 650 carb, Air-Gap manifold, roller timing chain, and headers. This engine will make plenty of torque, work with a stock convertor, run all your accessories and idle smooth with a slight "growl" in the exhaust. And it would cost half what he spent at Summit yesterday!
How I usually recommend building a street engine is to use a 10:1 (at the most) forged piston, port the stock 202 heads, get a 280 series cam, roller rockers, 650 carb, Air-Gap manifold, roller timing chain, and headers. This engine will make plenty of torque, work with a stock convertor, run all your accessories and idle smooth with a slight "growl" in the exhaust. And it would cost half what he spent at Summit yesterday!
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
If it's the kit I think (HLY-300-503-1) ... cam specs at: Lunati cam with 235°/240° duration at .050, .490/.490 in. lift, and 112° lobe separation.
I echo all the above ... plus ... it ain't gonna have enough compression to get out of its own way. Stock motor has dished pistons ... holley heads' chambers ~68cc. He'll be dang lucky to get 9:1 compression ... even with a thin head gasket ... even less w/ the recommended FelPro 1003. Low compression + big cam = sluggish turd in traffic. If y'all proceed as above he'll be dissatisfied. Is holley or summit gonna be at your side to guarantee he ain't gonna be pizzed at you? ... NO!
If you install aftermarket Flattop pistons ... will put him at about 9.2-9.6 ... depending on gasket ... still too much cam duration.
I echo all the above ... plus ... it ain't gonna have enough compression to get out of its own way. Stock motor has dished pistons ... holley heads' chambers ~68cc. He'll be dang lucky to get 9:1 compression ... even with a thin head gasket ... even less w/ the recommended FelPro 1003. Low compression + big cam = sluggish turd in traffic. If y'all proceed as above he'll be dissatisfied. Is holley or summit gonna be at your side to guarantee he ain't gonna be pizzed at you? ... NO!
If you install aftermarket Flattop pistons ... will put him at about 9.2-9.6 ... depending on gasket ... still too much cam duration.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I have and still run a big duration cam in my motors. I do run a 5 speed with a 3.70 rear so I can get away with this. The cam you are talking about is going to be to much for the setup that you have. As said above you need some compression and some gears to make tha tcam run good on the street. A better cam would be something in the 220 to 230 @ .050 range for that setup. A little more converter than stock won't hurt but it will have plenty of torque down low. 
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
I would go with something from 210-224 degrees @ 0.050 maximum. Some of the smaller Comp Cams XE series cams should work well. REMEMBER to use a oil additive for cam lobe wear if your running a flat tappet set-up. I like Valvoline VR-1 racing oil with a high ZDDP additive package.
Instructor
Joined: Feb 2006
Posts: 240
Likes: 0
From: Allentown PA
with Jackson...if the compression ratio is under 9.5...way too much cam...he'll hate it. I was always taught the lower compression ratio, the shorter the cam that is needed for it to react responsive on the street...that cam may sound good at idle, but it'll run like a 3 legged obese dog, especially at lower RPM's.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Instructor
Joined: Aug 2005
Posts: 183
Likes: 1
Yeah,
I think I'll suggest the Comp Magnum (Summit# OCA-12-211-2). This cam is 224/224 duration at .050 with 470/470 lift. This should give him the best of both worlds, acceptable low end torque but still a little "growl" to make it sound cool through the sidepipes. I have used this cam on a couple of different engines and liked it as a good street cam.
He can then put the Lunati cam on Feebay.
WDYT?
I think I'll suggest the Comp Magnum (Summit# OCA-12-211-2). This cam is 224/224 duration at .050 with 470/470 lift. This should give him the best of both worlds, acceptable low end torque but still a little "growl" to make it sound cool through the sidepipes. I have used this cam on a couple of different engines and liked it as a good street cam.
He can then put the Lunati cam on Feebay.
WDYT?
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
OK ... but also take a look at Summit's own cams ... 1103 or 1104 ... I like the 1103 for this ... Cheap too!
Yeah,
I think I'll suggest the Comp Magnum (Summit# OCA-12-211-2). This cam is 224/224 duration at .050 with 470/470 lift. This should give him the best of both worlds, acceptable low end torque but still a little "growl" to make it sound cool through the sidepipes. I have used this cam on a couple of different engines and liked it as a good street cam.
He can then put the Lunati cam on Feebay.
WDYT?
I think I'll suggest the Comp Magnum (Summit# OCA-12-211-2). This cam is 224/224 duration at .050 with 470/470 lift. This should give him the best of both worlds, acceptable low end torque but still a little "growl" to make it sound cool through the sidepipes. I have used this cam on a couple of different engines and liked it as a good street cam.
He can then put the Lunati cam on Feebay.
WDYT?
Thread Starter
Instructor
Joined: Aug 2005
Posts: 183
Likes: 1
After at least some consideration, our customer is still adamant in favor of the big cam. I am not sure what to do at this point. I just hope that he remembers this discussion if he is not happy with how his car runs or does not feel we tuned it properly.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
Racer
Joined: Jun 2005
Posts: 400
Likes: 11
From: Lubbock Texas
Do a search for the Peformer Rpm cam on this forum. I remember a few posts about how "miserable" this cam was in their street driven car & they were glad to get rid of it. It's specs are very simmular to the Lunati in question. If it were me I would do my best to convince your cust. to go with something smaller for the setup he will be running. Might be a diffrent story with a manual trans & some good gearing.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Put his wishes in writing, get it on paper, Document your conversation about the cam, give him a copy, and you stick one with the w/o. Then when he starts moaning about street manners, gently remind him it's what he wanted - with proof.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
They never seem to remember the conversations after the fact. Make sure it is in writing AND he signs it.
Thread Starter
Instructor
Joined: Aug 2005
Posts: 183
Likes: 1
I'll try to get it writing when the short block comes tomorrow. We got the first shipment from Summit today, with the engine kit and some roller rockers I was not expecting. I also found a box that read, "Racing Carburetor". It is a Holley "Street" HP with no choke, or even a provision for one, and mechanical secondaries. This is definitely going to be a racing mill. How that works with 309 gears will be interesting. Perhaps I can talk him into changing to 4:11s? I have a 4:11 drop-in just waiting.....
