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lemans-tom 09-29-2004 04:05 AM

help me identify the engine
I've used this message board before with great success so I'm hoping your collective wisdom can help me out again.

Here's the deal - I'm going to look at a 1976 El Camino this Saturday. However the lady that's selling it is a bit confused about what engine is in it. She says its a Chevy 455 (454?) and is 1965 - h'm something not right here me thinks.

I've done some homework looking at introduction dates for big blocks. So lets assume that she's got her dates wrong and its some form of GM engine either big block Chevy of some capacity, or a BOP 455, or the original engine (SB 350 or 400?).

The bottom line is how do I identify between all of these different combos, if I've only got a visual inspection in a crowded engine bay. Are there some particular details that will help, eg shape of rocker cover, number of bolts on rocker cover, water pump shape/size/ fixing etc .

I'm a Pontiac man so my experience lies here. Do all GM heads have the same method of date coding as Pontiac as this would help with dating at least.

Thanks in anticipation for any help.

MI2600 09-29-2004 10:06 AM

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You should be able to easily ID between a Chevy SBC and a BBC by the width of the valve covers. The SBC cover is just under 5" wide (edge to edge). The BBC will be probably 2"-3" wider. (Sorry, I can't convert that to metric.)

If it's still an SBC, you can tell the difference between a 350 and a 400 by the harmonic balancer on the crank. The 350 balancer rim will be smooth all the way around. The 400 has a section about cut out.

A good site for Chevy block and head #s is

poncho62 09-29-2004 10:42 AM

Would help us a lot if you could post a picture.................

lemans-tom 09-29-2004 10:50 AM

Thanks so far, that helps me to narrow it down somewhat. Don't worry about the metric thing, not everybody over here is a paid up member of the metric club. My age group tend to use both interchangeably.

I'll take a digital picture when I go on Saturday and post it here, but I might have to make a buy decision there and then, so any identification may be after the fact.

Thanks so far.

poncho62 09-29-2004 10:52 AM

If the valve covers have 4 bolts, it's a small block. If it has 7, it's a big block.

Best that I can do for now.

lemans-tom 10-01-2004 01:30 AM

Just to update this thread. My constant telephone questions to the seller has finally ground her down and she went and looked through some of the piles of paperwork that comes with the car.

It turns out that its an Olds 455. So a happy ending, thanks for your help, I've learn't something I didn't know before and that seems like a result.

Any advice or comments about Olds 455s?

DoubleVision 10-01-2004 07:56 AM

The olds 455 is a undersquare engine, in other words, the bore is smaller in inches than the stroke, it has a 4.125 inch bore and a real long 4.250 inch stroke, this engine is the holy grail of torque monsters, even in low performance smog profile it`ll roast the tires off. Joe Mondello is famous for what he can do with Olds engines, he also carries alot of performance parts and recommendations for them.

lemans-tom 10-04-2004 09:35 AM

Thanks for all the info. Just to complete the story I now have a 1976 el camino with 1968 Olds 455.

BTW I found a very informative site, that has quick visual rules of thumb for identifying different GM engines without recourse to casting numbers etc.

See the link below, page down about 5 times and click on 'similarities:other GM engines'. Perhaps it of use to to others and could be put in the knowledge base?

Courtesy of

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