406 rebuild cam and heads selection

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406 rebuild cam and heads selection

Postby spyderhunter » Fri Mar 15, 2019 4:32 am

Well my 406 is finally getting put together after many years of waiting. I decided to use the Comp Cams S12 238-2 Extreme energy 262H Hydraulic Flat tappet cam and stock 202 heads. The engine is a 1972 four bolt. Upon examination of the heads I found the typical cracks on one of the heads. I want to keep the engine reasonable for power, economy and drivability. Should I hunt for another matching head, or invest in a new set of aluminum heads that will work with this cam? I have an Edelbrock performer intake with a Quadrajet that ran pretty well before I tore it down so I plan to use them. I am not sure what my best option is to keep it breathing efficiently. I am going to run a 2004r and probably use the stock rear end with 2:29 gears for now, but plan to upgrade to 15 or 16" wheels when money allows me to. I would appreciate any and all of your technical wisdom to help me get this thing back together so I can drive this thing someday. Hopefully this summer!
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Sun Mar 17, 2019 7:09 am

Well, I guess I am going with new aluminum heads. NKB 64cc 2.02/1.60 from Skip White Performance. Probably should go with the Brodix or Dart head, but these have good flow numbers and are over $500 less.
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Re: 406 rebuild cam and heads selection

Postby cjbiagi » Sun Mar 17, 2019 11:01 am

Sounds good, keep us posted how they work out.
Clyde.........75 Monza 2+2
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Re: 406 rebuild cam and heads selection

Postby Fastmax32168 » Sun Mar 17, 2019 2:30 pm

What size are the runners on those heads? Are those the 200CC I found when I googled. If so thats a really tiny cam for a 406 with those heads. Its going to pull like a tractor right off idle, but it will run out of gas on the top end. You should consider a larger cam, a big motor like that needs more than you will on a typical 350.
JMHO
Roy
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94 Corvette Convertible LT-1 500+ HP
83 Malibu Wagon 383 EFI "The Longroof"
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Wed Mar 20, 2019 6:31 am

Well, I don't plan on driving it in the higher rpm range very often and think I would rather have the pull on the low and medium rpm range. I know it's not a big cam and don't think I need one, I don't think I need to have big top end power to enjoy driving it on the street. I could be wrong, but with the 2004r overdrive for cruising, I think I'll have more than enough power to get me to town and back. Time will tell though. Let me know if I'm way off because I am no expert for sure. The heads and intake are on their way and the bottom of the engine is together with the cam in. By the way Fastmax; How are the Mirage flares holding up with the SEM panel adhesive? I did the same thing to my car, but haven't had a chance to drive it yet. Wondering if the bond was still good after rumbling and driving conditions.
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Re: 406 rebuild cam and heads selection

Postby Fastmax32168 » Wed Mar 20, 2019 9:14 pm

The flares have exhibited no issues.
My opinion is the motor will run better with more cam. I tried the opposite of you, I tried to kill off low end torque on my 406 and was unsuccessful. My cam is a monster compared to that and the motor still has so much low end I have huge traction issues anytime I stomp it. Have you downloaded the comp camquest program and built your engine combination in it? That will give you the info you need and its free.
http://www.compcams.com/downloads/register.asp
Roy
77 Monza Monster Mirage!
94 Corvette Convertible LT-1 500+ HP
83 Malibu Wagon 383 EFI "The Longroof"
A V8 Trailblazer project
And A Gaggle of Motorcycles
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Wed Mar 20, 2019 9:22 pm

Great to hear about the panels staying put! No I have not used that program at all and did n't know about it either. I have asked several builders about it and have had differing opinions on which cam to use. Some want all top end power and some say to keep the power in the range you plan to use the most. My gears are fairly high so I figure that will tame some of the torque while giving me the top end and maybe keep some fuel mileage too. I will check out that program though. Thanks for the tip. Also, I just read another post about the 383 and 406 needing a different oil pan? I assumed the stock monza pan would work.
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Sun Mar 24, 2019 9:12 pm

Wow! You guys are right, it really IS dead here. I thought in 4 days someone might chime in, but ....wow!
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Re: 406 rebuild cam and heads selection

Postby avewhtboy » Mon Mar 25, 2019 2:55 pm

I have a 412 (400 60 over) that I put a set of iron Vortec heads and and let me tell you it was a screamer. Now I had 11.5:1 compression but it ran like a scalded dog until the oil pump pick up fell off :shock:
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Tue Mar 26, 2019 7:29 am

Well, I hope it just runs and pulls good enough to have some fun! I really like the stance of your car. What size are the wheels/tires and did you modify the suspension?
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Re: 406 rebuild cam and heads selection

Postby spyderhunter » Tue Mar 26, 2019 9:04 pm

Ok, I just read alot of your posts on your frame and suspension build and it obviously must have been worth all of the effort, but for now it's out of my league. I have to admit though, It's got me thinking about a future project on the Mirage. One thing at a time though.
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