Expanded Blueprint Specs:

  • The first thing you will notice is a whole lot more data than you get from the NHRA Tech Bulletins pages. That is why individual engines are shown rather than every available engine for the year-make.
  • The additional data that is not included on the NHRA Tech Bulletins pages is not authorized or approved by NHRA so do not assume that this has the same authority in those areas as the information on the official NHRA Technical Bulletins. The data from the NHRA web Technical Bulletins is included here and every effort is made to ensure that this data is the most up to date information published by NHRA.
  • An interesting tool is the link on the right side of the page to show all the cars that use the engine you have selected. You will find that information valuable in considering options for class placement for this engine.
  • You will find all the relavent information from NHRA for accepted replacement parts - pistons, rods, oil pans, etc. - is all located in this one page. You do not have to look anywhere else to find that information.

Engine Blueprint Specifications:  1962 Pontiac 405 HP 421 V8

PONT-62      Issued: 3/7/1962      Last Revised: 8/5/2014      Revisions: 6-1-62, 8-13-62, 02-03-03, 8/5/14 PC

Engine Family:   General Motors, Pont V8 Early         Advertised Comp Ratio:   11.00:1         Induction:   2-4 Bbl         Engine Type:   V8


Basic Specs:BoreStrokeMain Journal DiaRod Journal DiaMax BoreMax StrokeMax Displacement
 4.093"4.000"3.000"2.250"4.173"4.015"439.3 ci



Piston-Rod Specs:Piston WeightComp HeightPin WeightRingsRings WeightRod C/CMax Rod C/CRod WeightMin Assy Weight
 NANANANANA6.625"6.650"NANA



Compression:Deck HeightHead GasketPiston TypeDome/Dish VolDome/Dish HgtComb Chamber VolMax Compression
 .000"No SpecNo SpecNo SpecNo Spec66.8 ccCannot calculate



Valve Train:Int Rocker RatioExh Rocker RatioIntake ValveExhaust ValveLifter TypeSpring TypeLifter Dia.
 1.65:11.65:11.920"1.660"SolidOuter & inner0.842"




Camshaft:Intake LiftExhaust Lift 
 .465".465" 



Cylinder Heads:Casting No. Intake VolumeExhaust Volume  
 540306   421 SD
 544127   421 SD





Intake Manifolds:Casting No. 
 542991Aluminum    Runner Type
 9770319Aluminum    Runner Type
 9770859Aluminum    Runner Type



Carburetors:NumberManufacturerTransTypePrimary ThrottleSecondary ThrottlePrimary VenturiSecondary Venturi 
 AFB-3433SCarterALL4-Bbl.000".000".000".000" 
 AFB-3435SCarterALL4-Bbl.000".000".000".000" 




Notes:  
 ValvesUses 1.92" intake valve and 1.66" exhaust valve on 540306 heads. Uses 2.02" intake valve and 1.76" exhaust valve on 544127 heads.
 EngineStandard production line items for the 405hp 421" engine in the Catalina Models 2347 or 2311 include the use of aluminum hoods, fenders, bumpers, etc., and are allowed in Stock classes.
 EngineAll models allowed the use of aluminum bumpers which have been used previous to 1962.



Power Factors:Stock Man Stock Auto S/S Man S/S Auto GT Man GT Auto GTFwd Man GTFwd Auto 
Base Factors38512/19/0238512/19/02405 405 405 405 405 405 
Exception: Pontiac Catalina3601/1/213601/1/21            




Accepted Replacement Oil Pans for Stock Eliminator

Engine Group - Pont V8 Early           Effective 5/10/2022

Manufacturer Part Number
Milodon 30770
Moroso 20492

Accepted Replacement Blocks

Manufacturer Part Number
K&M Performance MR-1
All Pontiac APSJB


Accepted Replacement Connecting Rods for Stock or S/S

    Effective 8/23/2023
Specs:     C/C Length- 6.625"    Min Weight- 760g    Journal Dia- 2.249"    Big End Dia- 2.375"    Pin Dia- 0.980"

Manufacturer Part Number C/C Length Wgt. Pin Dia.
Carrillo C427-76635S 6.625" 834g 0.990" Pontiac
Carrillo C427-A76635H 6.625" 787g 0.990" Pontiac **Discontinued**
Carrillo P-455-SS 6.631" 760g NA SUPER STOCK ONLY
Carrillo P-455-SS (2) 6.625" 760g 0.000" Super Stock Only
Childs & Albert 389-12 6.625" NA 0.947" Pontiac
Crower F91059 6.625" NA 0.981" Pontiac
Crower ML93015B5 6.624" 773g NA SUPER STOCK ONLY
Crower SP93419 6.625" 830g 0.947" Pontiac
Eagle CRS-6625P3D 6.625" 760g 0.947" Pontiac
Eagle CRS6635 6.635" 830g 0.990" BB Chev
Manley 14168 6.635" 830g 0.990" BB Chev
Molnar Technologies PH6625WRB8-A 6.623" 769g 0.980"
Oliver ORPPONT6625 6.625" NA 0.981" Pontiac
Oliver P6225PONT 6.625" 790g 0.980" Pontiac
Oliver P6625PONTFR8 6.625" 819g 0.980" Pontiac

Note the calculations for actual displacement the maximum actual compression ratio.


Would you like to see a list of all the cars where this engine is used? Click here:

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