I've got my eye on an engine for sale here and the seller claims it's a '69 350/350 factory crate unit, which would make it an L46, I believe. I'm also aware that GM made a 300hp motor with the same block casting (3932388).

Block casting # 3932388
Head casting # 3927186 with 2.02" / 1.60" valves

Here are some pics...













From the information provided, does this look like an L46? Would it have pink rods? Are those pistons domed? Finally, if I was to install it 'as is' with those heads and a Comp XE274 or Magnum 280 cam, do you think 400hp+ is realistic?

Thanks,
Ian.

 

Ian,
I do not have my book of numbers wioth me for dealing with the block, but I know that the 186 heads are right for a 69 Vette.

Pink rods are correct for that era also. Thsoe are good rods, strong metal. And by the looks of the pistons , they appear to be the high compression pistons 10:1 +.

DO not have the specs on the cam that you wrote about to compare it to the strock cams.

Depending on wether the exhaust valves have hardened seats installed,(which is needed if using unleaded fuels) you may have an issue due to the possible high octane fuel required to make this thing run to peak performance. May need to be higher than 93 octane. compression can be adjusted (somewhat) by the thickness of the head gaskets and how far the piston get to the block head deck surface when rotated.

Everything looks fine....but....I always worry about buying a pre-assembled engine. There may be hidden issues that would need to be checked out my a qualified machine shop/engine builder to make sure that you are not buying a "grenade". I have seen it many times, the engine runs like a "bat out of ...." and then detonates unexpectably due to internal issues not readily seen.

I guess it is depending on how much they are asking for it.
And yes, I think if assuming that everything is correct, it should produce 400+ HP or at least have the capability to produce it when the other parts of the engine are chosen and installed , such as ignition, exhaust, carb, intake, etc.
"DUB"

 

According to this site, the block (3932388) is a 69' 327/350 with 2 or 4 bolt mains. The heads (3927186) are 69-70...302/350......Camel hump,64cc chambers,accessory holes.

Gary

http://www.mortec.com/castnum.htm

 

Thanks guys. Anyone know what the cam specs would be?

Any estimates on power if I kept those 186 heads (unported) and slapped a Comp XE274 or Magnum 280 in there?

Thanks.

 

The 388 block was used for both 300 and 350hp engines. In any case it's been rebuilt making it diffuicult to claim it's anything in particular. I doubt you'd get anywhere near 400HP, but WTFDIK.

 

It's just been freshened with new rings, mains, etc. Cam and heads along with CR dictated by deck height, pistons and cam make power, so there's no reason to say it would make 'nowhere near 400hp'. Assuming everything is OK, that combo with the stock cam should be making 350hp, so with a bigger cam, I'm hoping that 400hp+ is realistic. Anyone else care to comment?

 

Sure, I'll dive in! My original 350/300 motor has those heads, but the later 3970010 block. My understanding is those heads aren't that great compared to what is available on the aftermarket today. The only real difference between the 350/300 and the 350/350 is the cam - the carb and distributor are slightly different, but just to fine-tune the engine with the different cam.
Remember, those 350 horses were the old gross "flash" method, no accessories, no car type air filter and housing, and no car type exhaust. By flash, it means they just ripped it up to a max reading.

Pink rods were high strength rods offered by Chevrolet over the counter, so it's very doubtful that motor has them unless the builder put them in, and then you have to ask why just preimum rods and nothing else.

I'm with Mike Ward on the power potential you are asking about.

 

Just for giggles, how much is he asking for the engine?

 

$1,900. BUT, I'm in the UK and SBCs are rare, hence why you're sitting there open-mouthed at the price.

It's actually a pretty-good price over here.

 

Correct. Your engine was rated using the now disused 'gross' horsepower method, so by today's standards it never made 350 hp in the first place, possibly 275-300.

Would a simple cam change give your 50 MORE horses on top of GMs best offering for the year, or 30 better than an LT1. Don't think so.

 

Understood. I did wonder about the gross/net HP thing.

I'll probably be using the heads off my existing motor anyway (Holley SysteMAX aluminum). With those heads, a biggish cam and around 10.2:1 CR, I'd expect 400-450hp.

 

Good to see he's hit the pickup on with a mash hammer wonder what other parts have been "heavy handed"on or in