Stockish 340 upgrades, cam needed

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And in all probability the cam the wife would like the most. Good area under the curve and good street manners, probably even sounds like a stock 340 cam.
Howards Cams Hydraulic Flat Tappet Camshafts 711451-08
And on the street, not a bad cam at all in a heavy vehicle with around 9-9.5:1. Probably a lot of pinging going on with 10.5:1 though.
 
No, afraid the 5767 springs are a lot lighter than what Howard's recommends and the Edelbrock 9736 retainers are a little loose, too. Here's the springs for the howards .904 specific cams. There is a PAC single spring that can be shimmed to 1.77 installed height for the same pressure with the proper shims for about half the price, though. Here’s the Howard’s springs.
Howards Cams Performance Mechanical Flat Tappet Valve Springs 98438
 
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Kim, I like ya a lot and so I’ll just tell ya straight up your screwed. The *** clown wants it his way? Give it A lame *** cam and call it a day with no warranty or do overs. In fact, let him make the call because your about to tell him it is impossible to do. What he wants is ether impossible or expensive. Let him sort it out.

If he was any kind of smart, this thread would have never taken place and you would be done and paid with this job. I bleed for ya. BTDT. Lost a friend... except I didn’t know he wasn’t a friend at the time. Good riddance to bad trash.

Leave this job alone.
 
This should be good with 1.6s Should I get the pistons milled then to bring the compression down. This thing will be balanced so I would like to mill the pistons if need be. The old grind is the Comp 270/470. I convinced him to change it to take advantage of the new cams that are light years ahead of most old stuff. Kim
 
oldkimmer said:
Should I get the pistons milled then to bring the compression down.
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I think you would be better off with .053" head gasket and .015 piston pop up(.038 Quench)
then a 0 deck piston and a .053 head gasket aka .053 quench = NO Quench!

Also .015" is not going to change you compression enough to worry about it. but will destroy Your quench!
 
Well Rumble, I have lots of patience and willing to listen to what everybody has to say. I told him today that we could keep the steel heads or do the non CNC heads. Then run his stock exhaust manifolds. I know he won’t go for any roller or solid cam. This is the same motor I had to get a 340 crank for. Maybe I should of got light pistons for it instead. But that didn’t happen. But now the short block will be together as soon as we figure to mill the pistons or not, then get it balanced. Kim
 
I’m here to learn to as well. I’m as old school as u can get. I probably forgot more than I know. Just that some things are drilled into my head that I can’t get out or won’t. I may be to stubborn to let it sink in. Kim
 
I always first recommend using the springs that the cam grinder but, here is PAC single spring that comes close to a Howard's 98438. 416 pound rate instead of 420, and has an actual I.D. of 1.06 like the Edelbrock 5767 so it could be used with the 9736 retainers. I would rather see a full O.D. retainer to match the springs, though. But, for someone in a pinch, these still fit the usual 1.49 inch diameter Edelbrock spring pockets. And I have also found that you always need to double check Summits spring information to the actual spring manufacturers catalog. They are seldom 100% correct on I.D. or O.D., as is the case here. If set at an installed height of 1.77 (.030 shims), the seat and open rates are the same as the Howard's double springs.
PAC Racing Hot Rod Series Valve Springs PAC-1927-16
 
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I think with that last cam suggested by GE
Proud piston for a good quench of .038
And that you live 2200 feet above sea level will help as well.

It may need a slower centrifugal advance springs (stiffer) added to the distributor.
Or at the vary worries, have to kill a couple of degrees of total timing out of it, in the heat of the summer.
 
That does seem like a good cam. We will get the recommended springs. It’s a ***** getting things across the border. Hopefully it opens around the end of April. But that just my guess. Kim
 
Note, I edited posts, I had left the 9 off the spring number and posted the cam in by accident (Doh!). That’s close to being an outer edge spring for a juice cam, with 120 pounds seat and 350 open. I expect that’s a deal where you break it in with only the outer springs and then immediately change oil and install the inner springs. And good call Cudafever in the tuning. The closed chamber aluminum heads with quench at .038 and a slow advance curve with proper plug selection will be fine on 93 octane. I would like to see the curve Halifaxhops would do for this. I’m thinking for 91 octane it may even be close to a stock 70 or 71 two stage curve.
 
Jim @ racer brown! I get lost with all the technical info but if you talk with him about your set up, he can build the cam you want in every aspect. Usually 2 weeks or so and it shows up. The guy is well worth the call. Even for just the knowledge. Good luck with your pick.
Scott
 
oldkimmer said:
Ok, since this build changed a lot I’ve decided to start a new thread. 1970 340. Stock crank, rods with beams ground down and shot blasted. 2332 forged 10.5 pistons. The pistons are .015 a ove deck. The will be mills down for zero deck. My buddy has decided to go with TTI headers 1.5 to 1.75 step headers. Full TTI X pipe exhaust. Speedmaster CNC heads. LD340 intake, 650 dp Holley. This is a street cat that won’t be raced. The wife will be driving this also. He would like us to pick a cam that will take advantage of these CNC heads and TTI system. This is a 4 gear car with 3.23 rear gearing. 1973 Cuda. Thanks. Kim
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I think with the 3.23 gear and 10.5 comp. with alum. heads 224 @ 50 on a 112 centerline would work real well. The highest lift with 1.6 rockers or higher. Remember the alum. heads effectively reduce the comp. ratio. I would try to up the comp. ratio to 11.0 also. Just my 2 cents worth but copper pennies. The old 68 manual cam is a excellent choice always.
 
Kim, It sounds like your customer wants the best of both worlds. I agree with Rob, it sounds like no matter what you do, the customer wants it his way & any direction you go you are going to be wrong. I have had customers like this in the past & it's a "NO WIN" situation, sorry, just my opinion.
 
I was gonna use the Fel Pro 8553 that r .053 compressed for .038 clearance but then that really isn’t quench.
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Thats not quench?
Sure sounds like quench to me.

To be blunt though....... you’re not really going to be able to “take advantage” of those heads with a hyd cam on a 340 that will be run with 3.23’s.
Where those heads will start to shine on a 340 will be beyond the onset of valvetrain instability(valve float).

Just cam for how the car will be used, then iiwii.

That Howard’s cam GE posted is probably going to be as good as anything....... up to the point where the valvetrain gets unhappy.
 
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Just a hypothetical from looking over flow numbers. A set of OOTB Edelbrock Magnum heads with a set of 1.7 (SBC) rockers on the .506 lift cam looks very good for a strong streeter with good drivability. Intake flow of around 250 CFM from .400 to .600 combined with the fast ramp cam with the bulk of the duration concentrated from the .200 lift sweet spot.
 
Now that we're getting close to an agreed combo........i guess i will throw and wrench into the gears.

So this eng is not for "the one making all the decisions".........but for his lady.........who wants (i'm *** u me ing) a fun spirited motor, aka all bottom end and probably even wanting some gas mileage(within reason)

Garrett Ellison said:
That’s close to being an outer edge spring for a juice cam, with 120 pounds seat and 350 open. I expect that’s a deal where you break it in with only the outer springs and then immediately change oil and install the inner springs.
Click to expand...

With a fast ramp(to take advantage of the head and get some lift in there.) it may make the Hyd lifter a little unhappy aka noise. and a quit Exhaust system will even add to that.

A mild cam (read lots of bottom end torque ) will raise the running compression and, my not be so happy on pump gas..............

Here is my thoughts.
These forged pistons are heavy and have a lot of crown or are vary thick on the top.
What about having(someone that knows what they're doing) cut a "dish" in the piston top, opiset of the quench pad of the head.
If you could get 20 to 30 cc of dish, it could lower the compression down into the mid 9s or 10 on compression AND still have your .038"of Quench. Then you could install that torque cam........something that still has a lope to it but.......well, like the chry .474/280 cam.(have a custom cam built for the situation just giving an example of size)

Only thing this don't address is the potential of the ported SM heads. But i think the lady will have more fun driving it.
 
Edit X head have a average cc combustion chamber of 74cc the SM heads have 64 so maybe only 10-15 cc dish would work just fine.
 
I told him yesterday that the non CNC heads I feel would be a better choice as I think they will work better down low. I told him he will likely loose some low end grunt with the CNC heads. Then I told him that the new cams are light years ahead of the old Comp 270/470 cam in there now. He agreed to a cam change. That’s why I posted this thread. I will use the CNC heads. Kim
 
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