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406 sbc 13to1 dome pistons

19K views 40 replies 9 participants last post by  ericnova72 
#1 ·
I have a 400 sbc I paid 500 dollars for it has trw forged 13to1 forged pistons with stock rods I have a doug herbert hydraulic roller camshaft 286-291 adv 246-253 585-600 lift 106 lsa I have a set of 58cc cast heads on it now 205 -160 valves rpm air gap intake 750 vac secondary carb like to no estimated hp and will this be a good street strip combination also a 3000 stall converter need help with combination that will help make it work in a 81 buick regal turbo 3500 transmission 3:73 rear gear need help u guys
 
#4 ·
. Are those " 13:1 " pistons with 64cc heads? Or with those 58cc heads? Will the domes actually fit into those small chambers? Yeah, sounds like about 500+ HP as long as those aren't otherwise stock heads for a 305" engine... mid 12's to mid 11's in 1/4... 115 - 120 MPH... depending on traction... need some kerosene or other octane booster...
 
#5 ·
Just a guess, those are TRW #L2311f pistons??

If so, you've got about 13.8-1 with a 58cc head...tell us more about the heads if you want a decent HP guess...what are they, what's been done to them??

It won't run on pump gas, no matter how much octane booster you use...needs either E85, 108+ octane race gas, or straight methanol/ethanol alcohol for fuel.

What's the scoop on the heads??
 
#14 ·
I can't find a doug Herbert cam that matches your definitions with out a timing card it's not possible to calculate the DCR. without the DCR there is no telling what 13 to forged pistons mean.

Need the cam card?

Need the piston part number?

Whose 58cc chamber head?

My knee jerk reaction is you need to worry more about how the keep the heads from being blown into the next county or with those short rods when the pistons will be driven through the cylinder walls rather than how much power this might make.

Bogie
 
#17 ·
My cam is the dougherbert hydraulic roller camshaft part is c6k piston number is l2311f I do have access to some forge flat top 406 pistons with stock 5.7 rods
Seems there is some discrepancy between what you have according to spec's, and what you think you have.

The 2311 piston is a domed 400 piston for the 5.565" stock short 400 connecting rod, listed as 13.25-1 comp with a 64 cc head. With the head milled to 58cc, you are now at 14-1 comp, and the dome is very likely to hit the head on the now milled down heads...so you will need to do some careful checking and hand fitting there, either milling/grinding on either the dome or the combustion chamber for clearance.

The Herbert #C6K matches up to the specs you give, but it is a SOLID ROLLER CAM, not a hydraulic roller, and will need solid roller lifters, not hydraulic.

Even if you switch to the flat top piston and 5.7" rod combination compression ratio is still going to be too high for pump gas, if that is what you need to have the engine run on. Will be right around 12-1 with those pistons.

Going to the 5.7" rods will require clearance grinding on some of the rods to clear the cam lobes, unless the cam is ground with a reduced base circle to clear this type of rod and 400 stroke combination. Flat-tops will get you away from the dome-to-chamber interference problem with the 58cc heads though...but you will still have valve-to-piston clearance checks that will need to be made, could be a problem there...another pitfall that comes from milling the heads so much.

Beginning to sound like maybe this pile of parts is a little over your head, as far as experience and knowledge of how to get it together are concerned?? Or is this an already assembled engine you bought?? Or an assembled short block, and you are planning to install the 58cc heads?? No shame in admitting it, we all started somewhere, but be truthful so folks here can try to guide you through problem areas. :confused:
 
#18 ·
406 combinations

Well my combination seems to a complete bust guys can u help me I want to use my 406 block cause its a good block need help with a hood combination that will help get my 81 buick regal in the low 7s maybe high 6s really dont want to use nitrious if so maybe a little
 
#20 ·
Well my combination seems to a complete bust guys can u help me I want to use my 406 block cause its a good block need help with a hood combination that will help get my 81 buick regal in the low 7s maybe high 6s really dont want to use nitrious if so maybe a little
. Adjust your current combo as needed to get it running and add 5.38 rear end and slicks for 7's in 1/8 mile...
 
#22 ·
Then sell what you have, start over,,.....cheapest route? Any entry level alum head, low compression forged rotater, Vic Jr intake, hanger 18 modded 750DP and an EBay GT45 turbo.... short filled block, on low boost it will make 600+....on big boost it will make 800+ till it splits the block.
 
#24 ·
Some of what you have may work out fine, but you haven't given much clear info about exactly what you actually have in your possession to work with.

You've been very vague about what you have, is this an bunch of parts you have, or are you planning this and all you have are a few of the pieces, starting with the block??

What brand 58 cc heads, and how much port work has been done to them?? What part # is on the flat- top pistons?? What rods and crank do you have, be specific as to brand, style and length.

Most importantly....does this have to run on common pump gas?? If so, 600 hp is asking for a whole lot naturally aspirated.

If the heads are decent, the flat-top piston/5.7" rod combo, with the solid roller you have (CC6K?), on race fuel or E85, a single plane intake like a Holley Strip Dominator or ProProducts Hurricane with a 150 shot could get you to 700 hp....with a better rear gear than the 3.73 you have(something like 4.30 or 4.56), a well set-up chassis and good tires you can run in the high 6's.

The pump gas/3.73 gear/hydraulic roller limitation is what really hurts, if you have to keep those three criteria. .

We can help you get there if you tell us all the details on what you actually have.
 
#25 ·
As a current owner of a 406 your expectations of the motor are way out from reality.
#1 those 13:1 pistons require Race Gas at least 110 octane.
#2 the 406 block would have problems soon down the road (upper cylinder walls will crack)
#3 the lower portion of the block need to be filled with block filler and crank Girdle installed.
#4 Machine work in the cooling passages and steam holes is a MUST on 400 Blocks.
IMO do as I did.
I used a all forged rotating assy (Callies Crank, Oliver Rods, wisco flattop pistons)
Got a 2 stage nitrous system.
runs on 93 pump gas.
runs low 10s all day.
 
#34 ·
Yes 7 flat in the 1/8 not the 1/4 I have new flat top pistons and a set of I beam 5.7 rods I sold the old stuff guys also have I set of eq heads 64 cc heads been port polish and angled milled 3 angle valve job 205 160 valves a set of solid roller lifters team g matching intake and a 3500 stall 750 vac carb hei distributor th 350 tran and a set of 456 gears and now give me some hp estimates and forget im I want to shot a 200 shot of nitrous and I sheaded about 300 to 400 pounds of the car now talk to me guys
 
#39 ·
Yes 7 flat in the 1/8 not the 1/4 I have new flat top pistons and a set of I beam 5.7 rods I sold the old stuff guys also have I set of eq heads 64 cc heads been port polish and angled milled 3 angle valve job 205 160 valves a set of solid roller lifters team g matching intake and a 3500 stall 750 vac carb hei distributor th 350 tran and a set of 456 gears and now give me some hp estimates and forget im I want to shot a 200 shot of nitrous and I sheaded about 300 to 400 pounds of the car now talk to me guys
. What are "eq heads" and do you know the intake port size? Cam durations at .050" lift?
 
#37 ·
Get yourself a set of 1.6/1.5 split ratio set of full roller rocker arms, run the 1.6's on the intake side.

Get some 1-3/4" primary x 3" or 3.5" collector diameter long tube headers (Shoenfeld, Hedman, Hooker, Dynatech).

Is your HEI stock, or has it been upgraded with better module and coil, or hooked to an aftermarket ignition box??

Make sure you have adequate piston to valve clearance,... and cam lobe to connecting rod clearance, especially if cam is not a small base circle grind, and rods are not pre cam-clearanced.

Make sure your rear suspension/axle/driveshaft are ready for the increased power. Get a good sticky tire, lots of choices there. 350 trans needs to be well built, with the HD intermediate drum/sprag upgrade to survive.

Twin fuel systems, one for nitrous, one for the engine.

Still going to need 100+ octane, so pump 91-93 is not good enough...don't even try it.

Will be close to 475 hp or there about, plus the nitrous...low 7's to high 6's potential is there, up to you to tune it and get car set-up to use it.
 
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