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396 cam choice

Discussion in 'Engine & Performance' started by idahovette, May 15, 2020.

  1. idahovette

    idahovette Full Access Member

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    Building a .030 over 396 using a 66 passenger car 2 bolt block. Forged pistons ,10.25 pop ups, 890 heads with 2.19/1.88 valves. Trying to figure out what cam to use. Going in a 68 Nova with either a 400 or a 700R4 and a 3.42 10 bolt positraction rear. Not gonna race(much wink-wink) but it needs to get out of it's own way. Don't want to run too much of a converter, maybe 1900-2100, but no more. Give me some thoughts. Also will have Weiand and probably a 650 or 750 carb..... What's everyone think??
     
  2. Catbox

    Catbox Full Access Member

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  3. Catbox

    Catbox Full Access Member

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  4. Bextreme04

    Bextreme04 Full Access Member

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    I had my original hydraulic roller cam(Gen VI 454) reground to a better cam profile by Delta Camshaft in Tacoma, WA. It took them about a week from the time I mailed it to them and it cost me $144 all in. I shipped them the cam and they called me when they got it in to discuss what I wanted done with it. They also will sell you a brand new cam that they can grind to any spec you want. They have been around for a long time and have a great reputation in the forced induction and some import areas that historically have a very hard time finding off the shelf solutions from the big Cam guys.

    Mine turned out great and I wouldn't hesitate to use them again.
     
  5. Poppy 87

    Poppy 87 Supporting Member Supporting Member

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    If you are going to race at all, forget the 700R4, stick with the 400
     
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  6. Bextreme04

    Bextreme04 Full Access Member

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    I'd be a little concerned about a 3.42 geared 10 bolt holding up as well, especially with a posi. That rear end hooking up is gonna blow that rear end to pieces sooner or later. See if you can find a 3.73 geared 12 bolt to go with that TH 400 and you'll be golden.
     
  7. idahovette

    idahovette Full Access Member

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    Thanks everyone for the thoughts. I also contacted Comp Cams tech support and just received an e-mail back. I had already looked at some of their grinds and kinda picked one out that I felt comfortable with. Turns out @Catbox, Comp Cams and I all think alike. The Xtreme Energy 224/230 is what we all chose. Thanks again for the help guys! @Bextreme04 Your guys are going down on my list ,sounds like a great place. We have beat on this poor 10 bolt severely with hi-horse 327/4speed and so far so good, I would like to find a 12 bolt but they seem to be few and far between. @Poppy 87 , you are totally right about the 400, Probably the BEST GM trans made, PG close 2nd. If this was all up to me I'd probably run with an M22, but this is my son's car and his daughter, my grandaughter and him are gonna be behind the wheel. Trying to make it as easy on them(and me) as possible. Thanks again ALL!!!!
     
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  8. Wumbo

    Wumbo Full Access Member

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    upload_2020-5-15_21-9-44.jpeg

    Assuming good dual plane intake, 750 carb, pocket ported heads, and good headers.

    Tire destroyer. :happy107:
     
    Last edited: May 15, 2020
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  9. idahovette

    idahovette Full Access Member

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    Great info, Rob @Wumbo I just hope everything turns out like the graph. I think it's gonna be FUN !!! I'll probably have a tough time letting go of it and not wanna give it back.
     
  10. bucket

    bucket Super Moderator Staff Member

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    My very first thought was 'why?' but then the price answered that question, lol. The GM V6 folk say good things about Delta as well.

    I'm assuming when they regrind cams, they normally have to change the base circle? So if it's an engine with non-adjustable valvetrain, you still must convert to adjustable?
     
  11. MikeB

    MikeB Full Access Member

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    You probably have an 8.2" 10-bolt. Not exactly up to the task of handing big block torque. At least a torque converter will ease the blows to the drivetrain!

    I'm not a BBC guy, but would keep cam duration @ .050" in the range of 220 degrees, for example 218 intake/228 exhaust. The only cam companies that ever gave me rational advice were Crane and Jones Cam Designs. They almost always (or used to) err on the conservative side. Not so with CompCams. Did Comp even ask for your head port flow numbers?

    Finally what do you plan to use for gasoline with 10.25 compression and iron heads? Pump premium may not even cut it.
     
    Last edited: May 16, 2020
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  12. varmit86

    varmit86 Full Access Member

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    A 9" is a better choice much easier to find and super easy install in the leaf spring Nova. Gear swap super easy as you just swap out the third member if you want a change. 31 spline unit are very plentiful now days.
    The 400 is the only way to go and with a big converter more fun than a 4 speed to drive and fast as hell.
     
  13. QBuff02

    QBuff02 I like Big Blocks and I cannot lie Supporting Member

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    I'll throw in my $.02 here. With that compression ratio on iron heads I would err to the side of caution. It's going to be literally right on the edge of pump gas. As a matter of fact my 454 comes out to 10.3:1 and unless I knock some timing out of it, it will NOT run on pump gas without problems. Now apples to oranges, I have a Lunati VooDoo 268 in mine but it's ground a couple degrees off of the "spec" cam card. And looking back I probably should have went up one cam size to help the pump gas problem or installed this cam a couple degrees late instead of degreeing it right to the as ground cam card. The problem I ran into is with the engine specs and the way it's put together, the dynamic compression is around 8.8:1-8.9:1 and its really above the limit of pump gas. Now to that effect I run Sunoco 110 and leave the timing and engine where it's happy. I don't drive it enough so the high octane fuel isn't that big of a deal.

    Now, onto the cam of choice. Not all cams are created equal. If you start looking at the duration numbers at different points you will see that some cams are bigger or smaller than others when you start looking at .004, .050., .100, .200, .400, etc timing events. And some cams are better than others. Some have a lot of velocity and are very aggressive in their opening and closing rates. If I was going to buy a cam "off the shelf" it'd behoove you to look at similar cams from Lunati in their voodoo line. The same guy that designed the original XE cams for Comp is the same guy that went on to design the VooDoo cams for Lunati and he uses an updated profile on them with an aggressive opening rate but a slower closing rate than Comp and the cams make more power and are quieter than their comparable Comp counterparts. they open the valve fast but set it down slow. And most of the cam profiles are bigger throughout the range than Comp. But one of the standards for advertisement is to use the @ .050 numbers and most times things look "equal" when they really aren't. I'd look at a 262 (219/228 durations @.050) or 268 (227/233 @.050 but would probably be one size bigger than what you would want) voodoo from lunati. However, either way you will be quite happy! The Comp's just tend to be a noisier cam and I've had a few go flat over the years so I tend to shy away from them anymore. The local engine shop does too. But cams falling in those sweet spots for "street" whether its comp, crane, lunati, isky, etc. are what a lot of people use, because they've been proven and worked well for ages!

    The other thing I would add, is if you're running any kind of performance camshaft with domed pistons, I would absolutely check your piston to valve clearance! Here's one area where you do NOT want to overlook. Especially with oversized valves and longer duration cams, you will get awfully close, and you'd much rather have to flycut the pistons/massage the reliefs before you assemble for the clearance you need as opposed to tuning 'er up on the throttle and the valves hits the pistons and trash the engine. Most off the shelf pistons have larger than needed reliefs due to the fact they try to account for those tolerances and build it into the piston but it's still an area I wouldn't leave unchecked.

    No matter what you decide, I hope you have tire replacement funds allotted into the budget, because you will need it.

    :driver:
     
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  14. Ricko1966

    Ricko1966 Full Access Member

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    He was asking about cams but somehow everyone started talking rearend so here goes.I've blown up 4x 8.2 10 bolts. 1966 chevelle,zero deck 355, .510 292 intake,.535 302 ex. Cranes version of Rhodes lifters, good heads, single plane etc. TH350 car. 1972 GM built the corporate 8.5 10 bolt, internally real close to 12 bolt.Should be an easy swap from a later Camaro or Nova.Cheap and strong and used for decades carrier,posi.etc.all swap 8.5 truck to 8.5 lemans to 8.5 whatever.
     
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  15. idahovette

    idahovette Full Access Member

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    I failed to state the 10 bolt positraction unit that's in it IS out of a 74 Nova!! Has done well in the past......That's probably the kiss of death!!! LOL
     
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