# Block ID



## foreevergoat (Oct 24, 2011)

Like to ID a Pontiac Firebird block to see if this could have been a dealer conversion. The block is as follows. 043376 YH. Any help would be appreciated.


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## O52 (Jan 27, 2019)

The number you gave is the block serial number for the particular year the block was cast and does not indicate what model it went into.
YH was used on many different Pontiac models
More information is needed such as the block casting number and date. Both can be found at the back of the block near the distributor.

Dealer conversions would normally use a Service Replacement block and would not have the YH designation



*Year **Engine**HP**Engine code**Trans**CR**Cam**Head Code**BBL**Carb No.**Misc*1965421338 HPYHA10.506776 / 97787761-43898SBlock Casting # 9778791 Should have full head production number under valve cover - 97787761966421338 HPYHA10.50670921-44037S4-bolt main Block Casting # 97826111967428360 HPYHA10.50676701-47027262Block Casting # 97861351968428375 HPYHA10.5067161-47028268GP Block Casting # 97929681969428360 HPYHA10.5066461-4702926845 deg int. Bonneville Block Casting # 97929681970455360 HPYHA10.0067151-47040262Big Car /1970 - only year hi comp 455 Block Casting # 97991401972455185/200 HPYHA8.20667D41-27042064Early head no center exhaust divider Block Casting # 4854281972455185/200 HPYHA8.20667L41-27042064Block Casting # 4854281974400190 HPYHA8.02554X1-27044066Block Casting # 4819881975400170 HPYHA7.62665C1-27045160Block Casting # 481988/late 500557?1977301135 HPYHA8.2868011-217057172Block Casting # 5259341978400180 HPYHA7.74716X1-417058264Block Casting # 568557/500557


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