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Discussion Starter · #1 · (Edited)
Hey guys, I just got done restoring my '67 Chevelle, and I'm wanting to spice up my 396 just a bit without breaking the bank. I've got a '67 2 bolt main casting number 3902406 w/ '71 402 open chamber heads #6272292, and an RPM Performer manifold w/a 650 Holley DP. I know I'm going to hear the old why don't you build a 454 thing, but this is what I want in the car to stay as original as possible. Wanted to know if the heads that I have are something I can work with to build a nice street car. I also would like some opinions on pistons, cam, etc.... Would love a nice street car that runs good on pump gas, with a little lope in the idle.
I am running an M-20 with a 12 bolt posi and 3.42 gears at the moment, was thinking about going to a 4.10 posi for some fun on the street. Some say go 3.73, but others say it won't be much different then what I have now. I respect the opinions of the guys on this site and just need a little guidance. Thanks in advance for any help. Remember, this is a budget build!! Nothing elaborate or over the top. Would like to be in the 400-450 HP range if possible.
 

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Nothing wrong with a baby rat. Go for it. My opinion, keep the 3:42 gears. Those are perfect street gears with that 4 speed. 400 h.p. should be a breeze. Do a quick search and you should find TONS of info on cams, pistons etc. Here's a recent post that may be of use, your situations are similar:
http://www.chevelles.com/forums/showthread.php?t=345740
 

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Discussion Starter · #3 ·
Nothing wrong with a baby rat. Go for it. My opinion, keep the 3:42 gears. Those are perfect street gears with that 4 speed. 400 h.p. should be a breeze. Do a quick search and you should find TONS of info on cams, pistons etc. Here's a recent post that may be of use, your situations are similar:
http://www.chevelles.com/forums/showthread.php?t=345740
Very similar situation with the guy in the thread that you posted thanks...

Need some ideas on cam, pistons, valves etc... Was looking into a 280 Comp Cam, also looking at Lunati. Any opinions there? Looking to stay with a FT cam, unless someone gives me a good reason to go "roller".
 

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Budget build, roller cam will kill the budget for sure. Nothing wrong with flat tappet (although hydraulic roller is better), just make sure you follow proper break in procedure and use oil with proper zddp levels or a zddp additive. There is a sticky in the performance section about oil etc. Stick with stock valve sizes in my opinion, 396 breathes plenty good with them. Lunati is probably the best off the shelf cam out there. Pistons, I would go with a forged set just for durability sake in the event of detonation etc. As far as dome size etc. you'll have to ask or do a search, out of my limited knowledge. I can tell you to have head cc's checked to make sure exactly what combustion chamber size you have. This will tell us/machinist what piston dome size to use in order to keep compression down to a reasonable level, say 9:1 or so.
 

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Discussion Starter · #5 · (Edited)
Budget build, roller cam will kill the budget for sure. Nothing wrong with flat tappet (although hydraulic roller is better), just make sure you follow proper break in procedure and use oil with proper zddp levels or a zddp additive. There is a sticky in the performance section about oil etc. Stick with stock valve sizes in my opinion, 396 breathes plenty good with them. Lunati is probably the best off the shelf cam out there. Pistons, I would go with a forged set just for durability sake in the event of detonation etc. As far as dome size etc. you'll have to ask or do a search, out of my limited knowledge. I can tell you to have head cc's checked to make sure exactly what combustion chamber size you have. This will tell us/machinist what piston dome size to use in order to keep compression down to a reasonable level, say 9:1 or so.
Matt, thanks for you opinion.... How much more would a nice roller setup cost me compared to the FT cam? If it's a difference of 4-500 bucks, it might be something I can get the wife to go for! She is still getting over the dough that I spent restoring the car!!! Would a 10:1 comp ratio be a little high for a pump gas street car? On the FT cam deal, I was thinking about an oil like Delo 400 or Rotella w/ some EOS.... Any thought on that? I have no patience for the oil debate threads, as they just seem to go on and on forever with too many opinions.
 

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A REAL good quality hydraulic roller set-up will be $1000 or more when it's all said and done. Flat tappet kit, about $250. Summit has a real good oil made by Spectro and Valvoline VR1 is good too. Both have enough ZDDP to support flat tappet cams. 10:1 is right on the fence for iron heads on pump gas. No less than 93 octane.
 

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Discussion Starter · #7 ·
A REAL good quality hydraulic roller set-up will be $1000 or more when it's all said and done. Flat tappet kit, about $250. Summit has a real good oil made by Spectro and Valvoline VR1 is good too. Both have enough ZDDP to support flat tappet cams. 10:1 is right on the fence for iron heads on pump gas. No less than 93 octane.
The highest octane pump gas here in Calif is 91... I haven't seen anything higher then that in many years.
 

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Use the lower gears...take advantage of a quick vehicle...more fun when you have smaller cubic inches...
I used the pistons listed below with "820" 113cc heads.
I wish I would have selected this cam
Xtreme Marine XM270H Hydraulic Flat Tappet Camshaft

Pistons:
Sealed Power #844-L2242F60
396ci Aluminum Closed Chamber Stock-Type Piston, .060'' Overbore
Piston Bore: 4.154''
Piston Top: 38.3cc Dome
Pressed Pin
Comp Ratio: 10.58:1 w/109.4cc Heads
Ring Grooves: 5/64'', 5/64'', 3/16''
 

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Discussion Starter · #9 ·
Use the lower gears...take advantage of a quick vehicle...more fun when you have smaller cubic inches...
I used the pistons listed below with "820" 113cc heads.
I wish I would have selected this cam
Xtreme Marine XM270H Hydraulic Flat Tappet Camshaft

Pistons:
Sealed Power #844-L2242F60
396ci Aluminum Closed Chamber Stock-Type Piston, .060'' Overbore
Piston Bore: 4.154''
Piston Top: 38.3cc Dome
Pressed Pin
Comp Ratio: 10.58:1 w/109.4cc Heads
Ring Grooves: 5/64'', 5/64'', 3/16''
Thanks Jim.... How does your car do on pump gas with the 10.58:1 comp? Who makes the Xtreme Marine cam, and why would that be your choice of a cam? Ernie
 

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Discussion Starter · #10 ·
Ok, so how many votes for the 4.10 rear for a car that won't see much highway time? Mostly a street cruiser with a few short trips of 120 miles round trip.
 

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Ok, so how many votes for the 4.10 rear for a car that won't see much highway time? Mostly a street cruiser with a few short trips of 120 miles round trip.
Personally, I'd stick with the 3.42s... 4.10s can be fun around town, but on those 120 mile trips, you will relegated to the slow lane with the semi trucks :D Well, really it just depends on what RPM YOU are comfortable cruising at... You can cruise all day at 75 MPH with the 4.10s, as long as you have enough oil and the cooling system works well... But psychologically, the sound of a BB screaming for hours on end can get to you...

3.42 should still be fun for a properly setup 396, and 3.73s are right in the middle...

As for the engine, you'll need to get pistons to match the heads (different than "1967" 396 pistons). IMO, probably want to stay around 9.5:1 with the iron heads. I used to run about 10:1 Compression, and it worked fine with 91 octane, but my cam was pretty wild, bleeding off cylinder pressure...
 

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M-20 and 3.42 gearing is sweet....great (for street) launching and fair cruising. Leave it alone. Lots of BBC head swaps. IN the 70s, guys would put 1971 and 72 heads on their cars to bring the CR down. I take late 70s 454 shortblocks and put early heads on them to bring the CR UP!

If the heads are in good shape, run them. 60203 Lunati would work. Also thinking the Crane/Summit 226*/.533" /108 LSA would wake up that engine....
 

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Thanks Jim.... How does your car do on pump gas with the 10.58:1 comp? Who makes the Xtreme Marine cam, and why would that be your choice of a cam? Ernie
with 113 cc heads you will have a little less than 10:1 compression. I like the idea of the marine cam having a wider torque curve...the cams suggested will make more torque but within a narrow peak curve...

With a "small" big block try to build as much torque early and longer if you can...it will really "take advantage" of a 373 or 410 gear.

just another opinion
 

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Discussion Starter · #14 ·
UPDATE: I have a friend that has a matching pair of heads in his garage casting # 3872702 that came off of a running engine about 5 yrs ago. He said that I could have them for 200.00. I'm thinking these might be a better set of heads to use on my motor than the open chamber heads mentioned earlier in this thread. Any comments,or advice would be great!! I looked up the number on the heads and found them to be a '66 model, closed chamber head used on both 396 and 427 engines. Thanks in advance for any feedback. Ernie
 

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That would change a whole lot on your build as far as piston choice. Those are small combustion chamber heads, requiring small dome pistons in order to keep your compression reasonable and also avoid piston to valve clearance issues. Not a big deal if you haven't actually purchased anything yet! BTW those heads are desirable and worth $200 all day long if they are not damaged beyond repair.
 

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Discussion Starter · #16 ·
That would change a whole lot on your build as far as piston choice. Those are small combustion chamber heads, requiring small dome pistons in order to keep your compression reasonable and also avoid piston to valve clearance issues. Not a big deal if you haven't actually purchased anything yet! BTW those heads are desirable and worth $200 all day long if they are not damaged beyond repair.
Matt, Those heads were pretty beat up, and I opted for a set of heads that I found elsewhere, casting #3909802 that I'm picking up tonight. The heads are rebuilt, but do not have hardened ex valve seats. 300.00 for these. I believe they are pretty close to the heads that I mentioned previously. Do you think I should have new exhaust valve seats installed before I put the engine together? They are just factory spec rebuilt. Thanks, Ernie
 

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The chamber may be a hair bigger on the 802 heads, best to have the exact cc checked. You don't HAVE to have hardened seats, but it would be wise to at least have a local reputable machine shop check them for warpage, cracks and overall condition. I, as well as many friends have run engines without hardened seats and never had a problem. I suppose a daily driver/severe duty use vehicle would be different.
 

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Discussion Starter · #18 ·
The chamber may be a hair bigger on the 802 heads, best to have the exact cc checked. You don't HAVE to have hardened seats, but it would be wise to at least have a local reputable machine shop check them for warpage, cracks and overall condition. I, as well as many friends have run engines without hardened seats and never had a problem. I suppose a daily driver/severe duty use vehicle would be different.
Thanks Matt, I will have them checked out and look into the hardened seats to see what they recommend. Ernie

If anybody is looking for a set of 702 heads, I found another guy that has a set for 250.00. He is located in Santa Cruz Calif, and has an ad posted on Craigslist. I found them in the SF Bay Area listing. Too far to drive for me!
 

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Discussion Starter · #19 ·
I'm going to go ahead and get the seats done on those heads, as I found a guy that will do them pretty cheap... (friend of a friend deal) I am looking to get rid of my Performer 2-0 intake (not an RPM as mentioned earlier, sorry) and go with something else, but the other intakes that I've looked at say that they won't fit under a stock hood. Anybody have any suggestions on a good intake that will fit with a little better flow than mine? I'm going to either run the Lunati 60203 cam or a Comp 280. I also have a chance to pick up a Holley 770 Street Avenger carb for 200.00... Wondering if I will be over carburated with the 770???? Any suggestions would be greatly appreciated. I need to get my ducks in a row pretty quick, because my dad is flying in to help me build it on the 14th. Need to get parts ready before then!!! Thanks in advance for any help. Ernie
 
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