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400 sbc build

General engine tech -- Drag Racing to Circle Track

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rocketracer380
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400 sbc build

Post by rocketracer380 »

400 with 5.565 rods street/strip 6k max any thoughts
lefty o
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Re: 400 sbc build

Post by lefty o »

budget?
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Re: 400 sbc build

Post by rebelyell »

longer rod means shorter & lighter piston & lighter bobweight
min 5.7" but much better is 6.0"
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Re: 400 sbc build

Post by pdq67 »

I had a 406 with the short stock 400 rods in it and it ran fine.

But that said, I still dearly love the 3" stroked little engines up top!

I am going to shift my 325" engine, (4.155" bore x 3.000" stroke), up around 8,000 rpm just for sh*ts and grins!

Show the ricers what high rpm SBC power is all about!

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Re: 400 sbc build

Post by Baprace »

rocketracer380 wrote: Tue Oct 13, 2020 9:09 pm 400 with 5.565 rods street/strip 6k max any thoughts

rocketracer380 , I'm doing one right now , I am using Icon pistons IC757 -.030 dished forged pistons that yield approx 8.5 CR with 76cc heads / 9.5 CR approx with 64cc heads and I'm using Scat 7/16 bolt x 6 inch rods that fit without any alterations , clears a stock dimension street race cam 236* x 236* x 108* solid lifter cam (customer wants thunder) with plenty of room and I'm using the stock 400 crankshaft. Much easier to work with versus the 400 rods, BUT if that is all you have then I don't see any real big issues , except the piston weight is very heavy and Cam to rod clearance is a lot tighter and may require some grinding on the inner rod bolt.

rebelyell is telling ya fact.
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Re: 400 sbc build

Post by PackardV8 »

Yes, to all the above and yes, it all works. Using 5.7" rods is better and using 6" rods is best; but a low budget 400" fun car with stock rods will be fine.

The big difference is today 6" rods are only a slight step up in cost from reconned stock rods and they're much better. (and yes, stock rods need reconned) Same with pistons; the gooder stuff is only slightly more expensive than the tall, heavy short rod pistons.
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Re: 400 sbc build

Post by mag2555 »

Yes, how much does the car weigh and what rear gears are you willing to live with?
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Re: 400 sbc build

Post by prairiehotrodder »

i always give the advice on 400 builds that if you can find a .020 piston do that instead of .030. to start with.
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Re: 400 sbc build

Post by rfoll »

If your bore is original and straight enough, reusing the stock rods and pistons with a 64 cc chamber can get you to about 9:1 if you deck the block. And with any 400 build, it is advisable to deck the block to help the gasket seal. Vortec heads and a cam with 230 degrees at .050 will make it a street tire smoker. The stock pistons might be iffy over 5500, and some say the short rod wears the bore, but an original bore is already worn. Head studs are a very good idea on a stock 400 block. Compression is easily achieved with a 400, flattop pistons and a 64 cc chamber get you in the 11:1 range. KB seems to have the best selection of dish volumes to allow you to achieve the compression ratio you want.
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rocketracer380
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Re: 400 sbc build

Post by rocketracer380 »

i was thinkin 9.5/10:1 with vortecs and a crane 114691 290/298 dur .536 in .554 ex 112 lsa
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Re: 400 sbc build

Post by F-BIRD'88 »

rocketracer380 wrote: Thu Oct 15, 2020 3:09 pm i was thinkin 9.5/10:1 with vortecs and a crane 114691 290/298 dur .536 in .554 ex 112 lsa
Look at the 106 lsa version of that cam for a 400.
or the 280-288 244-252 106 (102/110) .518-.536 crane cam
for that.

Summit Racing CT-108 cam will work well to in that vortec 400. 282/286 248-251 .531-.542 106 lsa (102/110)
These are made by Howards.
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Re: 400 sbc build

Post by F-BIRD'88 »

If you want a hyd cam for this.. Call Comp cams and get a custom grind version of their XE284H-10 cam
Get it ground on a 106 LSA.. (102/110).
Simple as a phone call.

Will be custom 284-296 240-246 .507-.510 106 LSA
102/110
Last edited by F-BIRD'88 on Thu Oct 15, 2020 6:01 pm, edited 1 time in total.
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Re: 400 sbc build

Post by F-BIRD'88 »

Another good lil solid cam for this is Melling cam #22402.
282-290 240/250 .521.521 106LSA (102/110)

Hang on tight with any all these in a 400 sbc with vortecs.
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Re: 400 sbc build

Post by rocketracer380 »

do i need such a narrow lsa for a 406 i figure the 112 is better for nos
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Re: 400 sbc build

Post by lefty o »

you didnt say anything about nitrous. imo unless you are gonna hit it with the motherlode of juice, 108-110 is closer to where you want to be. there happens to be a decent cam guy here on the board, may be worth talking to him.
id lay out your criteria, and budget, then start picking parts.
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