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396 small block chevy

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396 small block chevy

Postby movetter1 » Wed Aug 15, 2007 11:28 pm

Hello, first time posting . I am thinking about building a 396 cube small block.How come they are not as popular as the 383.How much more does it take to install the 3.875 stroker in the 350 chevy block.I know you need .900 base circle cam and the correct rods.I'd be using brodix track1 heads and a solid roller cam.The goal would be around 500 hp with 11.5 compression for short street rides and some weekend 1/4 mile track use. The car weighs about 3400 lbs. and has 3800 stall and 4.56 gears with m/t drag radials.
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Postby Ed-vancedEngines » Thu Aug 16, 2007 3:31 am

Ok, this question is a little different.

There is nothing wrong with using the 3.875 for the 396 cu in providing the piston you chose and rods are compatable with the stroke in the block and you buy specially clearanced stroker rods. Still you want to check the rod vs cam clearances and you will need to do a ton of grinding on the block and the bottom of the cylinders to make it all fit with clearances of a minimum of .045 at the closest point.

I have done the 396 and an off version of it a 392 with good results.

Now why do I have any issues with your question?
You should be needing to tame this down to get the horsepwer you are seeking, and you can get ample of power as long as components compliment each other with 11.00 -1 comprssion and be more streetable.

Ed
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Postby RogerF » Thu Aug 16, 2007 7:39 am

I am building one of these right now using a Compstar (Callies import line) rotating assembly. This is the second one I've built using these components, and I must say these H-beam rods have as much cam clearance as any I've seen. They clear a 1.030" base cam fine. Lot's of grinding the block though as Ed points out. It's a good motor if you have enough head. I am in MD if you want to see it first hand.
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Postby EngineTech1 » Thu Aug 16, 2007 9:18 am

I agree, the biggest problem with long strokes in a normal SBC is block clearance and cam clearance. If you have a mill or someone will do a cnc clearancing for you it will save you a lot of time.
Small base circle cams aren't the best thing in the world either but they work just fine as long as you don't expect too much from them which from the looks of your post you won't.
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396 small block

Postby bigjoe1 » Thu Aug 16, 2007 9:56 am

I do the next step up from what you are doing. I use a 4.00 stroke, and you can use off the shelf piston for a 6.25 rod in a 350 engine. The performance is REAL good. With a mild (236 at 050 ) cam, and AFR heads, the last one I did made 570 HP at 5800 RPM, and 568 torque at 4500 RPM. The AFR heads come with 75 cc chambers, so yuo end up at around 10.5 or 10.6 to one. This is a sweet combo.
JOE SHERMAN RACING ENGINES
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Postby movetter1 » Thu Aug 16, 2007 9:57 am

Thanks for the replies,I assemble my own motors in the GOrage, lol.I'm just trying to get the most cubes for the money. The car is just for fun.I did not want to sound big headed with my power goals but I want go as fast as possible.My car is a 69 nova lightly streeted I take it to the track on a trailer.I would like to run pump gas on the street and race fuel at the track if needed.My current setup is a 355 with 11.5 comp and .570 lift flat tappet with victor jr. on the old sportsman2 heads.It has been 11.70@115 mph.I have a new 355 motor with kb 10.5 comp hyper flat tops, the track1 heads and a comp custom grind with 260* at .050 and .630 lift ,vic jr. and 850 dp.The 396 idea came when i was looking at the compstar and eagle websites.The 396 would have all forged stuff with the appropriate solid roller for the combo and I would have the track 1's ported by CBOGGS.
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Postby kwilliams » Thu Aug 16, 2007 2:16 pm

I've been looking at the 3.785 cranks pretty hard too. Glad to see that it's not an overly complicated combination to assemble.
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Postby AdioSS » Wed Aug 22, 2007 1:39 am

in what cases would you rather do a 3.875" stroke than a 4.00" in a 350 block? Maybe if you don't have enough cylinder head to support the extra cubes? Is there anything about the block itself that makes one better than the other? A longer stroke would give more average torque and would allow a higher compression ratio. The parts shouldn't cost much more for the longer stroke either. What compression height pistons and rod length would you use for each?
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Postby Ed-vancedEngines » Wed Aug 22, 2007 2:23 am

Off the shelf parts;
3.875 Eagle or Callies or (?) crank
6.00 Stroker Clearanced H Beam Rods Eagle or Compstar from Callies.
Piston with 1.060 compression distance off the shelf from BRC Performance

That will give a total ht of 8.9975 or you can call this 9 inches. With stock uncut deck this would give a .025 in the hole deck ht which I would like. If decks is cut it will be reduced by the amount of deck cut.

I prefer this combination becuase it gives a little more block room with less block cutting, Still a bunch to cut though. and it does not requre as small of a base circle on the cam. I agree though with Mr Joe. His 4 incher will make more power.

Ed
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Postby Competition Engines » Wed Aug 22, 2007 7:00 am

A word of advice. Get a small rod journal crank and rods and save yourself some clearance work (2.00" crank journal).
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Postby movetter1 » Wed Aug 22, 2007 11:35 am

Thanks for the tip Scott.This motor is in the planning stage ,I need all the info I can get.Are there any particular 350 blocks to use.I have a 1980 4 bolt from a 1/2 ton 4x4.
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Postby kwilliams » Wed Aug 22, 2007 1:56 pm

How hard is it to get a 4" stroke crank to fit in a 350/327 block? A 3.75 crank needs a little grinding to get it to clear.
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Postby movetter1 » Wed Aug 22, 2007 3:10 pm

The 4 inch crank in a 350 is new to me.I would definately prefer the largest engine I can build for the buck.Ed I looked at the BRC site and was impressed with their prices on cranks and pistons for my app.They also give great credit to you.I would really like to make more than 500 hp with this motor,I think my track1 heads can be ported enough to carry this motor.I am also thinking about a small nitrous kit to get into the 10's .A 400+ cubic inch motor is more attractive to me than 383 or 396 inches.I don't want the expense of buying an after market block.
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Postby Ed-vancedEngines » Wed Aug 22, 2007 3:30 pm

I have done several of the 400 block based 422 cu in engines that are in the 570 hp range in a daily streetable condition. These are fun to drive with instant resonse at any speed. They do take some good components and decent heads that work well but are not too large. The end result is fun with 92 octane fuel at 11.00 -1 compression.

Those do take a custom piston the way I do them though. I do a reverse dome in them. I have done this similar thing with more than one combination of pistons and rods and crank strokes.

The cams are my designs and are very streetable in a Hydraulic Roller with upper rpm limits of 6,900 rpm's They sound like a High Performance Chevy Cam but end up with in the neighorhood of 245 deg in and a 257 ex @ .050 so they do run decent for a Hyd Cam. They have good vacuum for power brakes or A/C etc.

I did a 10.30 -1 version of this that ran on 89 octane pump gas and still had over 500 hp.

They all did have ported heads though. Possibly the new AFR Heads in these combinations could be even better. I have been using ported Canfield 190's in them that were closer to 200 cc when completed.

Ed
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Postby movetter1 » Wed Aug 22, 2007 3:50 pm

400 blocks are hard to come by now a days and I don't mind setting the valves a few times a year. I already have the brodix heads they are brand new. Mo Grier
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