Got a Big Block Question?
 

:bowtie: Hey just bought a 454 Big Block (casting #14015445) this weekend for my 68. My question is does anyone know where I can find HP rating from the factory for this motor and on the block it is stamped Hi Perf, exactly what does that mean as far as why did GM stamp it on some blocks and not others. Also the heads that are on it are casting # (14081045) stamped Pass which I presume means passenger, and its got guide plates and studs. What size valves would they be? Also how many CC's would these heads be? Your help with any of these questions would be so helpful. You can email me at jirwin59@usadatanet.net. Thanks JoAnne

You can find most of the info you are looking for on www.mortec.com

All big blocks had guide plates an screw in studs from what I can remember.

Good luck with the BB!:D

Not sure if this is true, but originally if it had hi perf pass on it was because it had 4 bolt mains, but also it had extra oil passages for installing a remote oil cooler, (plugs just above oil filter) and I think they continued to put this on blocks that had the passages even though they did not have 4 bolt mains. Could be wrong on this but I have an old factory engine building guide that stated this about the oil passages. I've never bothered to check it on any later blocks as I've never run a remote oil cooler. Back in the old days when they ran big blocks in Nascar and road racing and such I guess they needed the cooler.

i had a couple big blocks in the past that said hi perf pass on them and they were both 2 bolt mains. the oil plug thing rings a bell but i can`t remember what it ment.

Oh yeah, I forgot to mention, those "045" heads, (if memory serves) should be the "good" open chamber oval port, w/2.06 and 1.72 valves, 119 to 120 cc's. These can be turned into a pretty good head by going to the larger 2.19 and 1.88 valves and mild porting. Not hard to pull 500 horse out of a 454 with the right mods with these heads. They used to be Lingenfelters (sp)heads of choice for street strip big blocks in the 80's before the boom in aftermarket heads.

I have two 396's that are stamped with the High Perf. and both are two bolts. From what I understand and have seen is that the HP blocks DO have the oil cooler holes machined into the block, but had nothing to do with whether it was a four or two bolt block.

I believe you are thinking of the "049" heads. Currently, they are one of the most sought after heads due to the design of the combustion chamber and ability to flow pretty good numbers. the "045" heads are more of a smog/truck head. Good for low end torque, but not much in the high rpm HP department, but still a fairly decent head.:D

I stand corrected, that's the ones I was thinking about, matter of fact I have a set but was too lazy to go to the shop and look.

Thanks Guys for all the helpful info, I got more out of your posts than I did from a ton of other sites on the net. Hey 67SS396 Do you have any suggestions how I could wake those heads up to make them a more desirable head if possible?

pass
 

I own a 427 with "pass" castings.
I've understood "pass" castings refer to passenger car versus
truck.Makes sense to me since 427's were only offered in passenger cars.
IMO

Re: Got a Big Block Question?
 

Seriously ancient thread, but in case others wind up here:

All big blocks said "HI PERF". PASS meant passenger or truck, but I've never seen a truck motor. Since I've never actually seen anything other than PASS, I can't confirm there's anything else. I'd imagine even if there were truck motors so stamped, ours would be passenger car blocks anyway.

I did see a 366, extra-ring, school bus motor and it was stamped HI PERF but I don't know about PASS.

I've owned a 396 2-bbl rated at (wait for it!) 265hp, gross. It was also stamped HI PERF.

So, HI PERF really just seems to mean "not a small block".

Re: Got a Big Block Question?
 

[QUOTE

I've owned a 396 2-bbl rated at (wait for it!) 265hp, gross. [/QUOTE]

I bet it wasn't in a 66 Pontiac though!!

Re: Got a Big Block Question?
 

This is a old thread I don't even remember it.

I have seen 366 blocks and heads with "truck" cast into them as well.

Re: Got a Big Block Question?
 

I like big blocks and i can not lie.

Re: pass
 

They put a lot of 427 tall decks in big trucks.

Re: Got a Big Block Question?
 

I bet it wasn't in a 66 Pontiac though!![/QUOTE]

No, 69. According to Wikipedia the 265hp 396 was available from 1961 on, which is clearly wrong. Pretty sure 67-69 only, and maybe 1970 as a 400.

Re: Got a Big Block Question?
 

I was under the impression the 2 bbl 396 was 69 only for passenger cars

Re: Got a Big Block Question?
 

I guess I should pull a valve cover and see which heads I have on my 396. My block casting number is 3902406 which according to MorTec is from 1967 and a 2 or 4 bolt main and I've never had the pan off so don't know which it is. My intake casting number is 3883948 and it too is for a 66-68 Oval Port Q-Jet off a 396/325 HP or ( and I wish I had this mill ) a 427/385HP. I am thinking the weak spot on my engine is the exhaust manifolds because they are from a 1973 454 Cop car engine and in that year I'd be surprised if the 454 had more than 250/275 hp. Like on a Mopar is the serial number of the car my engine came out of stamped on the block anywhere?

Re: Got a Big Block Question?
 

Not in the frozen north.
IIRC 66 was the first year for a 396 in a canadian pontiac. We got the chevy motors in our pontiac's up here.
I know the location of a 69 pontiac 4 door hardtop that still has it's factory 427/385 horse motor with turbo 400. All intact including a trailer towing package.
Remember, it's a secret. We don't want you big block luvin' guys coming up here and haulin' our poncho's back south. LOL!!

Re: Got a Big Block Question?
 

So was the 427/385 classed as high perf engine or a worker because you mentioned 4 door with trailer tow package in a Pontiac.

Re: Got a Big Block Question?
 

Two things:

1) 68250 is correct because he specified 2bbl. There were 4bbl engines 66+ but so far as I can find 1969 was the only year for the 2bbl 396.

2) There was no 427/385 - it was a 429/390. Or it was stickercharged. But yes, the L36 is the same as the Corvette L36. The "worker" engine you'd want for a wagon would be the 427/335.

Our cars (Canadian, at least on the prairies) were such poverty cars compared the the US. You could option them up, but almost no one did.

For example, in a 1969 2+2 the base transmission was 3 on the tree. With a console. The "shifter block off plate" is hard to find!

In the US, by mid-year the base engine in the US Bonneville was the 428. In Canada the base engine on the Parisienne was the 250 straight 6.

I guess that's probably more because they followed the Impala mechanicals and those were probably what the Impala line had as well.

Re: Got a Big Block Question?
 

All I can tell you is I rode in a 66 396 2bbl 3ott pontiac laurentian when I was 15. A red 4 door sedan. Definitely a 2 bbl cause we flipped the air cleaner lid for that air rush. Wasn't hard to tell what carb it was.
I started tinkering on all kinds of stuff when I was 10. New the difference between 2bbl's, 4bbl's, bbc's, sbc's, old hemis, and even a S.O.H.C. 427 Ford. Helped install a new set of timing chains on one.
I had a date coded 396 2bbl 67 motor that I rebuilt for my chevelle. Pulled out of an unmolested one owner wrecked pontiac. I knew the car from new.
The 427 was a 385 horse motor. Sticker on the air cleaner too! Quadrajet carbed too!
You could buy most anything you wanted back then. The dealers would order it for you.
Buudy's dad had a 68 Laurentian 4 door with a 327 and 4 speed with a 4.10 geared trailer pkg. Used to pull his boat to the lake.
Another guy we knew ordered a 70 SS chevelle 454 LS6 4 gear with a trailer tow pkg and 2.73 rear gear.
Back in the day you could get anything you wanted up here in the north.