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468 build help!

 
78bbctruck
I love my Chevy Chevette!
Posts: 1
Joined: 10/11
Posted: 10/20/11 04:31 PM

Just getting into the 4x4 truck pulling and wanted to know what you guy thought on a 468?  I have so set rules i have to stick with and they are 1. has to have oem cast heads 2. has to be able to street drive (this can be boarder line) 3. No race gas and has to have a 4150 carb.   Now we pull a 40,000 lbs transfer sled as far to 300ft. as we can.  We olny pull one gear so rpms are everything. Just wanted to know some opinions on what varibles would be best to put into a 468. thanks  

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chevelle83
I have an SS396 tatoo
Posts: 442
Joined: 10/08
Posted: 10/21/11 06:42 PM

imo,,, there really aint gonna be that much gain,,,,,,,,, I assume your are talking about a 454?  thats .060 over and that dont make any extra power,,,,,,,,, boring an engine only cleans up the bores,,,,,,   .030 on each side of the pistion does not make much power!

I think you would be best porting those heads,,,,, and get the right pistons to get your compression to about 9.5 max (pump gas)

a .515 to .530 lift cam with about .240 duration for pulling torque.

I think you would be good pulling it to about 5000-5500rpm

main thing with pulling is gearing, tire size, for your particular situation.

I just rebuilt a truck 454 and used the lunati 60200 cam its going in a dually. check out my thread

http://forums.chevyhiperformance.com/70/8854111/car-engine/454-rebuild/index.html  

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dond1965
V-6 Camaros rule!
Posts: 33
Joined: 12/13
Posted: 12/19/13 01:43 PM

one gear? rpms are everything? i suggest the 4.50 bore block with 3.76 stroke combo for 477 cubes. rectangle port gm head castings. solid roller cam with WIDE LSA for a wide power band [maybe 114 degrees] a 1,000 cfm carb.  

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dond1965
V-6 Camaros rule!
Posts: 33
Joined: 12/13
Posted: 12/19/13 02:34 PM

for fun i did a camquest6 dyno sim... [454] 4.50 bore x 3.76 stroke. 10 to 1 compression. open large stepped tube headers. for heads i selected 2-valve canted/hemi, pocket ported, large valves [2.19 x 1.88] single plane std. flow [like a victor jr.] 1,000 cfm 4-v carb. gasoline fuel. rated head flow is 311 cfm at 0.550 lift int.,  238 cfm at 0.650 lift exh. street/ level 6 solid roller cam #11-694-8 [10], with specs of.... 255-262 degrees duration at 50, 114 degrees LSA, 0.652 inch valve lift. the sim predicted figures of 653 horses @6.500 rpm, 600 LBS. FT. @5,000 rpm, with some room for over rev.  

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tuffnuff
Moderator
Posts: 272
Joined: 01/10
Posted: 01/09/14 04:34 PM

OK, I recently built a 468 BB and I believe that ALL your power is generated in the combustion chamber of your cylinder heads.
So I will post pics of the porting.,. step by step.
Castings 049, 781 and 782 are good oval port heads and fairly easy to find.
I have a good assortment of porting tools and each one has a different carbide burr for specific applications.

The Tools I use

Thetoolsiuse

Finishing Tool

Finishingtool

Oval top Peanut Bottom

5318

Getting Close

Gettingclose 1

Small Oval Ports

Smallovalports

Hogged Out Intake Port

Intport 1

Big Exhaust Port

Export 1

049 Intake And Exhaust Ports

049Intexports 1

Port Matched Headers

Portmatchheaders 1

Ported & Gasket Matched Eddy Top, Stock On Bottom

Gasketmatchportedovalsandstockedelbrockmanifold

Tricked Out 049 Ovals

Trickedoutovals

These ported heads flow about as much as stock rec port heads.,. all it takes is time, about 6 hours per head.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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tuffnuff
Moderator
Posts: 272
Joined: 01/10
Posted: 01/09/14 04:48 PM

You might want to find a set of beefy truck rods.,. same 6.135" length as stock rods.

Truck On Right Stock On Left

Truckbbrodonright

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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dond1965
V-6 Camaros rule!
Posts: 33
Joined: 12/13
Posted: 01/09/14 06:11 PM

dang tuff, them exhaust ports look almost like intakes!! wooo Shocked  

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tuffnuff
Moderator
Posts: 272
Joined: 01/10
Posted: 01/09/14 08:26 PM

Chuckles,,,,, yep after 5 or 6 hours per head they'll flow enuff unrestricted air to feed a 468

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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dond1965
V-6 Camaros rule!
Posts: 33
Joined: 12/13
Posted: 01/09/14 08:45 PM

right on!!  

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tuffnuff
Moderator
Posts: 272
Joined: 01/10
Posted: 01/09/14 09:11 PM

The OP only posted once and has not been back in almost 3 years.,. dond, are you tomb raiding again and raising the dead.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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