# 1971 engine Id



## joe 1971 (2 mo ago)

hello every one kind of new to pontiac's although i owed a 69 lemans in high school. i just purchased a 71 t-37 and i am trying to identify what engine I have and what the stock hp. might have been some one has done a few upgrades at least it has an after market carb and intake and pretty sure i here some kind of a mild cam. but any how the casting number is 481988 the date code is i belive I293. the nubers are perfectly clear i just mistook the I for a one at first the part that is confusing me is the stamped numbers by the water pump read 40719 YH and that does not make any sense to me. i realize that it appers to be a 1973 engine from the date code so someone must have changed the engine. but the casting number says 400 block but the YH does not match that.any advise on what might have happened or what this might be would be greatly appreciated.


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## Drewm (Jul 27, 2021)

Date code indicates September 29, 1973, which is a 1974 model year. YH code is a base model 400 from 1974.

Pontiac engine codes


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## ponchonlefty (8 mo ago)

if that is correct and the heads are correct. my book shows 225 hp net.with a 4 barrel.the 2 barrel is190 hp net. 8.0:1 comp. 330 [email protected] engine [email protected] [email protected] gross. 8.2:1 comp. 4 barrel. the book says they switched in 72 to net figures.


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## 1971LemansWisc (Apr 18, 2021)

These are the '71 Pontiac Engine Codes. 

CID HP Code 

350 250 HP WR,WU,WN,WP
350 250 HP XR,YU,YN,YP
400 265 HP WS,WX,XX,YX
400 300 HP WK,WT,YS
455 280 HP WG,YG
455 325 HP WJ,YA,YC
455 335 HP WL,WC,YE


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## joe 1971 (2 mo ago)

thanks for the info on my engine. my heads appear to be a 46 not sure of the info on those but I take it every thing is a base 400 with the exception of the add ons someone installed. but once again thank you. I guess I should have known enough to look ahead one more model year but didn't.

thanks every one


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## joe 1971 (2 mo ago)

joe 1971 said:


> thanks for the info on my engine. my heads appear to be a 46 not sure of the info on those but I take it every thing is a base 400 with the exception of the add ons someone installed. but once again thank you. I guess I should have known enough to look ahead one more model year but didn't.
> 
> thanks every one


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## joe 1971 (2 mo ago)

what would be considered a good set of heads for this 400. don't need the best or most expensive or rarest just trying to get some of that 70 71 hp back into it. i am finding a pontiac does cost a little more for parts. but that ok not everyone has one of those.


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## Jim K (Nov 17, 2020)

Everyone will have their own thoughts on this, but casting # 96 heads for a 1971 400 will allow you to run on pump gas, as will any of the 6x-8 heads..


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## BearGFR (Aug 25, 2008)

joe 1971 said:


> hello every one kind of new to pontiac's although i owed a 69 lemans in high school. i just purchased a 71 t-37 and i am trying to identify what engine I have and what the stock hp.


Note, there's an entry in the FAQ section here that has lots of "how to identify" information. The title in fact, is: FAQ:  How to identify your Pontiac Engine. 

Bear


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