Hi at all,

yesterday I phoned a guy who wants to sell his:

1977 K5 350cui automatic

He was telling me that it has about 300 HP because of some engine part swaps (Edelbrock, Holley, camshaft). After my objection that this alone cannot raise the HP from 165 to 300, he answered that it was originally a 265 HP 350cui engine...

So my question is: Was there really a 265 HP 350cui or another engine with "more" power in a K5 Blazer? The strongest I know is the 175 HP of the 400cui...

Thank you in advance,
Blazerum

 

just ask for a dyno sheet. that way you know if the seller is just pulling numbers out of his or her ****.

 

There are all kinds of hp range 350s out there! You did not mention if he is claiming it to be the original motor with modifications or a transplant.

There are also A LOT of people that read the hp number off of the packaging and then add all the numbers together and claim that they now have said amount of hp because of the parts they added. I mean you do know that every single sticker on a Honda add's a minimum of 10 hp automatically right?

 

As Rex said, it all depends on what it came out of and what's been done to it. You can determine the original application by reading the block casting code (driver side top of bell housing) and ID stamping (passenger side head mating surface).

Heads, intake, cam, and carb, I can see taking a 165hp engine to around 300hp. With a full build consisting of higher compression pistons, heads, intake, cam, and carb 300HP would be easy.

 

Thanks for your replay(s).

I know that there were more powerful engines even in the chevrolet concern (camaro and corvette had the 350 too) at this time, but was there a "original" K5 Blazer (maybe a special model?) with a 265 HP stock engine?

He told me that there are some original chevy 265HP-metal-badges inside and outside the car... so he really said that the car had stock 265 HP out of the chevy plant.

PS: Of course no dyno sheet... like ever

 

CLICK HERE for scanned images of the original 1977 Blazer brochure. This is what the General produced in 1977. No 265HP rated anything. The 350 was rated 165HP and the 400 was 185HP. Also, GM never put HP ratings on their vehicles.

I couldn't find anything through a few searches on 1977 special editions that would have had a hopped up engine package. That's not to say that some obscure up-fitter didn't do something like that, but it is highly doubtful.

Like I said, get the numbers off the block and then you'll know the origin of the engine. If you get head casting numbers (under the valve cover), we can identify them as well and tell you whether or not 265HP is outside the realm of possibility.

Or you could just drive it and see how it feels. There are many things that could make it feel more powerful, but if it runs, drives, and all around feels good to you, who cares what the HP rating of the engine is.

 

Exactly my opinion.

I will ask him for the engine code and give it a try.

BTW: I found a pretty cool VIN-Decoding-Sheet for old chevys (decoding by hand, letter by letter), is there something similar for engine codes of this time?

Thank you.
(PS: Thanks, really cool specification sheet)

Edit: For those who are looking too, I found an engine code decoder HERE

 

i always find it interesting how horrible the hp ratings were back in the day. we now have 4bangers that put out as much as the small blocks 30 years ago.

i have a 73 400ci engine in my 86 pick up, factory horsepower is 195. my 1993 s10 with the 4.3 has the exact same amount of hp lol. though the 400 has a wee bit more torque pushing almost 300. from the factory anyways