HEMI Technical Info

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Hemi Heads

Ken Veney Industries  / BNR / SSI
Fuel

Racing Spark Plugs

Intake Seats: 2.25"(stock),  2.4, 2.5, 2.6
Exhaust Seats: 1.900", 1.94 (stock), 2.00
Chamber Volume: 168 cc (stock) Original "fuel" heads had there own intake bolt pattern and intake manifold - later changed to the standard (?)  6 (10 bolt spacing not using the end bolts) or 10 bolt intake manifold pattern
 Thick Heads
Veney started this buy adding .100 to the deck surface     Read More
 

Alcohol  (Fat or Flat Head)
Designed for  alcohol engines only - Unique intake manifold dimensions, intake and exhaust bolt pattern, rocker arm stands,  valve covers, spark plug tubes ... etc
Chamber Volume: 90 cc

2.400 Intake x 1.900 Exhaust
2.500 Intake x 2.000 Exhaust
2.600 Intake x 2.100 Exhaust


Veney Alcohol (not all) and early  Fuel heads had a 90 deg intake manifold mating surface, for use with special Veney Manifolds.
Later the Fuel heads interchanged with BAE/AJPE etc.13 deg (stock angle)

 
BAE - Brad Anderson Racing
Fuel
Thick Heads   Read More
Alcohol - Fat Heads


( stage5 )

Stage 4-10
designed for  blown alcohol engines
( + A/F ) - Unique intake manifold dimensions, intake and exhaust bolt pattern, rocker arm stands, exhaust rocker arms, valve covers, spark plug tubes ... etc
BA-3?  or original fat heads -  128cc chambers 
Some times fuel heads are referred to as '3' heads.
 
BA-4  -  101 cc chambers
The 4's came out later and the only real difference was smaller combustion chambers. All valve train components, headers, intake, rockers, valve covers, etc., were interchangeable with BA-3.
 
BA-5  -  101 cc chambers  -  PM or TAFC
comes is two main versions which started about two years ago before that they only had a single version. They now have the alcohol and the A-Fuel head. The alcohol head comes in two versions one being for certain promod classes with small valve rules.  The head has a 2.425 intake valve. All versions of the 5 have the same valves. This head was offered initially as a dual plug head because that was the norm when they came out. Most blown alky cars were running dual mags, in addition to the A/F cars. Then came the next 'version' with CNC intake runners, which were predominantly single plug. The CNC intake runner heads flowed better and you can tell due to the slightly 'ribbed' finish to the intake runner. Some referred to these as '6' heads back in the day, but all of that went away when the real 6 came out.
 The A-Fuel head has dual plugs and smaller ports to keep the air velocity up.-
2.400 Intake x 1.900 - 6.55" long Exhaust
 
BA-6   -  96 cc chambers (2006)
also comes is two main versions also, the alcohol and the A-Fuel head. The alcohol head comes in two versions one being for certain promod classes with small valve rules. The head features a slightly raised intake port and a D-shaped exhaust port. Neither valve from the 5 will work, although all rocker gear will work. A .25" spacer is necessary under the intake to make the intake mate up with the higher intake runner. The alcohol version has bigger valves and better seat angles than the BA-5 head
 The A-Fuel head has dual plugs and smaller ports to keep the air velocity up and is basically the same as a BA-5 head. 
2.400 Intake x 1.900 - 6.1" long Exhaust
 
BAE 7  ???? -   96 cc chambers
is in the works that will combine the features of the 8 with the 2.400 valve to make it legal for Pro Mod competition.
 That's the story , why they skipped the '7'
 
BA-8  -  96 cc chambers
comes is two main versions, the alcohol and the A-Fuel head only.
The alcohol version has too big of valves for PM classes that have valve size restrictions .
The alcohol version has a reshaped chamber, better port and bigger valves that a BA-6. The intake port features a divider from the bottom of the intake floor to meet up with the divider in the top of the port  that diverts the air around where the valve stem enters the port. The head also features a 2.450 intake valve. The exhaust is the same as the 6.
The A-Fuel head has dual plugs and smaller ports to keep the air velocity up with reshaped chambers for nitro and different seat angles and valve sizes. The intake runner has a small vane in it on the A-fuel head to split the air and keep the velocity up.
 
BA-8 X -  96 cc chambers
has a different exhaust port, and takes a different header due to the flange angle being different.
2.480 intake ?
2.400 Intake x 1.900 - 6.1" long Exhaust

BA- 10   (TA1-X) - 96 cc
intake Raised (again)
2.5 ntake ?
1.9 - 6.1" long Exhaust

 Note: BA-5/6   or  BA-7/8/10  rocker arm assemblies are unique 
 Individual Rocker arm shafts
 
AJPE Alan Johnson Performance Engineering ( made from 6061-651 Billet Aluminum)
Fuel Stage 1 - 3  Generally - 2.4/1.95 valves
6 bolt intake manifold is a standard Fuel , intake and exhaust bolt pattern, rocker arm stands, exhaust rocker arms, valve covers, spark plug tubes ... etc

Stage 4 Same as above with added +.100 deck ( thick heads)

Stage 5 - 5.5 
same as above  loops instead of o-rings, larger intake valves, increased intake angle and raised ports, most exhaust seats are
55 deg seats

Stage  6 - 7 - 8  -- (requiring new valve covers, new spark plug tubes and new headers)
same as above ( thick heads) and additional material ( .5" ) added to top of head to move up the valve cover, intake angle, raised ports, -- Stage 7+ int an ex seats are 55 deg
 
A - 1/4 (stock) or 5/16 (NHRA required) v-cover studs (also found on stage V)
B - 7/16 or 7/16-3/8 studs for extra foot on rocker arm stands (also found on stage V)
C - intake side extra foot on rocker arm stands
D - optional on all "Fuel' heads 9/16 nuts on heads under the rocker arm stands---> common head stud
configurations are (1) 9/16 in block and 9/16 NF on top of head, or (2) a stepped stud to 1/2" on top of the lower row of studs, 9/16 (3) the top row can have a stepped 9/16 bottom, 9/16 middle (on top of the head - in a recessed hole under the rocker stands) and a top 1/2" nut to go above the rocker arm stands--------(early blocks were only available 1/2" - 1/2")
E - down lines now go threw the heads  ( ,5" taller v-cover rail )
X - spark plug tubes are also longer than stock or earlier  Fuel heads

Thick Heads    Read More
 
Nostalgia Fuel/Alcohol (not Fat Heads) 176cc chambers
Stage 1 ( similar to new fuel - hoops, seats, guides )

Designed for VRA rules( + A/F ) Uses AJPE fuel intake manifold dimensions, with smaller ports.
2.375/1.925 valves.
Stage 2
Designed for VRA rules( + A/F ) Uses AJPE fuel intake manifold dimensions, with more flow than
Stage 1.  2.4/1.925 valves.

Fat Heads (Muscle Heads)   (2008) designed for  TAD / A/Fuel alcohol engines ( small chambers )Compatible with BAE-5/6 intake/rockers/exhaust/v-covers/etc.
Stage 1 (A/Fuel) 94 cc,  2.4/1.9 valves
Stage 2 (Alcohol) 97 cc,  2.4 or 2.45/1.9 valves
Stage 3 (Alcohol) 99.5 cc,  2.6 /1.925 valves

 
JFR - John Force Racing

Fuel
6 bolt intake manifold and a standard Fuel, intake and exhaust bolt pattern, rocker arm stands, exhaust rocker arms, valve covers, spark plug tubes - copies of AJPE stage 5 or the raised v-cover surface of the stage 6,7,8....... the 200+cc (thick) version are .100" added to the block surface but do not have additional material on the intake, therefore when used on a std. deck block you need to use a .100" tall  style intake manifold ( common design to Veney and BAE - thick heads)       ----  Also some have FORD carved on them

 Thick Heads    Read More

Top is AJPE bottom is Force.  Note that you almost can't tell them apart

 
Dart   Fuel or Alcohol

Intake Seats: 2.25"(stock),  2.4, 2.5, 2.6
Exhaust Seats: 1.900", 1.94 (stock), 2.00
Chamber Volume: 168 cc (stock)

6 (10 bolt spacing not using the end bolts) or 10 bolt intake manifold pattern or stock 16 bolt configuration.

 

NRE X-1 Cylinder Heads (2009)
Alcohol - Fat Heads

 

WAR - Walt Austin Racing

Fuel

Small 16 bolt ports (and bolt pattern) but has an unique o-ring for the 6 bolt, big pattern manifold to bolt on. the ports wouldn't match ?


Alcohol

 

Co-Line  John Medlen and Randy Anderson  (2005?) --> sold to Dale Brand
- Alcohol - Fat head

TAFC/TAD 2.475" intake & 2.00" exhaust valves
Pro Mod 2.400" intake & 1.900" exhaust valves
4.375" & 4.467" chambers
+.100 deck, std deck or -.500 deck versions.
Compatible with BAE valve covers & headers (BAE intake manifold can be used with minor modifications)
Compatible with existing Stage V, Manton, Reid rockers and shafts.
A/Fuel version is also available.
An independent rocker system is also available.

 

Total Flow/ Chuck Ford

Alcohol
 
Keith Black
Fuel
 
Alcohol
 
Indy cylinder head
Gasoline
Alcohol
 

Stage V

Gasoline - Alcohol
Basicaly a stock ( modern ) replacement
Intake Seats: 2.25",Exhaust Seats: 1.900",
Chamber Volume: 168 cc

R/RB Block
10 bolt or stock 16 bolt intake manifold pattern configuration. Stock low exhaust port or raised port. Stock or aftermarket exhaust manifold/header bolt patterns available. Stock dimension (smaller) intake port openings available on special order. Machine heads for dual spark plugs

Stage V Conversion heads incorporate numerous revisions allowing them to be used on any B or RB wedge block


Note:  the original 16 bolt mopar intake bolt pattern and 2 of the " fuel" 6/10 bolt patterns

 
Mopar - Steel / Iron
Intake Seats: 2.25"(stock),  2.4, 2.5, 2.6
Exhaust Seats: 1.900", 1.94 (stock), 2.00
Chamber Volume: 168 cc (stock)

D - Series
During 1969 and 1970, Chrysler did some experiments in refining the Hemi cylinder head. Namely working with the various aspects of the design that affected the intake and exhaust flow. The most feasible ideas were designated for prototype or limited production use on the racing engines. These became know as the D heads.

D1
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1969 with the same intake and exhaust valves, but with larger ports. Each intake port had 3.00 sq-in and the exhaust port had 2.10 sq-in. Intake valve angle was 35 degrees; exhaust valve angle was 23 degrees.
D2
Alternate cylinder heads for circle track racing. Initially developed in 1969 it was essentially the same as the D1 but was overbored 0.02-in to create 429 ci (as permitted by NASCAR). This program was cancelled after about a month since performance gaines were not sufficient.
D3
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1969 using larger intake and exhaust valves. Intake valves were 2.38-in with a 3.65 sq-in intake port, and the exhaust valves were 2.00-in with a 2.53 sq-in exhaust port. Valve angles had to be changed due to the new intake valve size. Additionally, the cylinder bores had to be notched for intake valve clearance. Ironically, the power was less than the D1 program when power runs were made on May 9, 1969.
D3.5
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1969 using the larger intake valves and ports from the D3 and larger and straighter exhaust ports of the D4.
D4
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1969-1970 using the same intake valves and ports as the D1 but with larger area, higher exit and straighter exhaust ports. The first D4 head power runs on May 1, 1970, and the 426 Hemi generated 641 hp.
D4 A
Mullen made an aluminum version of the D4 head
D5
Alternate cylinder heads for the 426 race Hemi and probably the most famous of all of them. Initially developed in 1970 with all of the improvements of the D4 but cast in aluminum alloy using two spark plugs per cylinder. D5 Hemi heads had 2.35 intake valves and 1.94 exhaust valves, slightly larger than previous Hemis and round Ports More Information
D6
An aluminum alloy head with two spark plugs like the D5, only now included a further raised exhaust port.
D20 Magna
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1970 with substantially larger ports and a wider iron head to house the ports. The intake valves were 2.50-in with a 4.00 sq-in intake port, positioned 35 degrees, 45 minutes from cylinder bore center. The exhaust valves were 2.20-in with a 2.6 sq-in port, positioned at 36 degrees. The larger head design required larger cylinder head covers.
D21 Magna
Alternate cylinder heads for the 426 race Hemi. Initially developed in 1970 as an aluminum-alloy version of the D20 Magna.

  Casting Numbers
heads  
2468016 1964 426 (Cast K) Hemi
2488596 1964 426 (Early Production or Prototype Race) Hemi  Note - Square Valve Covers
2531110 -M 1965 426 (Alum "Alcoa") (direct connection Hemi heads)
2531110 -M2 new Edelbrock MP Hemi heads
2531695 1965 426 (Alum "Alcoa" Rev B)
2531718 426 (A-148) Hemi
2780559 1966-1971 426 (Cast Iron) Hemi
2945270 426 (Cast Iron D3) Hemi
3512015X 426 (D4) Hemi
3614433 426 (Aluminum) Hemi
Intake  
2468045 1964 426 Hemi 2x4 Aluminum Cross Ram (Super Stock)
2536900 1965-1968 426 Hemi 2x4 Magnesium Cross Ram (A990)
2780543 1966-1971 426 Hemi 2x4
exhaust  
2780508 426 Hemi Cast Iron (Passenger)
3418453 426 Hemi Cast Iron (Driver Side)