Learn me 366 c.i. chebby school bus motors...Challenge related

Ovid_and_Flem said:

dean1484 said:

What is a chebby?  A big fat guy eating a cherry?

Your thinking of a "chubby"...which is a big hairy fat guy that eats "twinkies."

 No that’s a bear. 

In reply to Fueled by Caffeine :

I stand corrected...thanks for your expertise in that area.;>)

In reply to Ovid_and_Flem :

I lived in Seattle for a few years.  

GTXVette said:Knurled, I don't think so on the crank snout, but Will check friday If for nothing else My own Info

To be fair, I might have mixed up my info between the Chevy truck engines at the Ford "FT" truck engines, which were like FEs but built to be overloaded.

In reply to Ovid_and_Flem :

You know I've put a lot of thought into your issue the last few days. I even walked away from the Thanksgiving table when I needed to research an idea that popped into my head. After all that thought it comes down to it has to be faster than the Vette is currently so go for it. 

 Daym, Jimmie That's Funny .

Stampie said:

In reply to Ovid_and_Flem :

You know I've put a lot of thought into your issue the last few days. I even walked away from the Thanksgiving table when I needed to research an idea that popped into my head. After all that thought it comes down to it has to be faster than the Vette is currently so go for it. 

Lemme guess you were so stuffed and moving slow so you naturally though of me and mah slug of a c4? LOL

A 366 from a school bus is definitely a Mark IV big block Chevy as others have said.  These were once ubiquitous as were their larger twin, the 427.  The 427 was even used in Chevrolet C90's (think 18 wheelers).  Most, if not all, 366 were medium duty truck engines.  All that extra beef was advantageous for years of heat cycles and near constant idling.  They have tall pistons and an extra ring.  Every one I've ever seen had a 4 barrel Holley of unknown (to me) size.  The intake manifolds are unique to these tall deck engines and you will need spacers to adapt to a light duty aluminum manifold.  I have heard of but never seen these spacers.  I have some older HP Books about rebuilding and Hot Rodding big block Chevrolets.  These tall decks are mentioned briefly and it is said that the 427 is something to consider for large cube build but the 366 should be avoided.  If I recall correctly, it was said that the 366 could not be bored and stroked to much above 413 or so cubes.

This being GRM though, I say go for it.  Anybody can go fast with the parts that are already proven to go fast.  That's boring.  Take some junk and prove everybody wrong...now that's something to see!

Don't bother.  I built a 427TD into a super cheap 11 second street running 20 years ago.  The intake, push rods and heavy pistons are all issues.  On a 366, the bore is so small that they run a smaller intake valve.  I looked into building one into a high boost engine a few years ago and it is not worth the cost to make into a performance engine at any HP level.  Even with a cylinder wall notch they are shrouded too much to bother with.  The 3.76" stroke crank may or may not be cross drilled.  If it's cross drilled don't bother with it.  If not cross drilled, it could be sellable or usable in the 454 block transplant (427).  But the free 366 will be an expensive engine to run in a performance effort.  454s are cheap now.  I currently own 2 tall decks, one has a 4.5" stroke (525ci) and the other will get a 4.5 or a 4.25" stroke crank.  The only reason to run a TD (10.2" deck) BBC is to allow a long stroke crank with long rods and a short piston compression heighth.  Both of our 4.5" stroke cranks are set up for 6.7" connecting rods.  If you added a big stroke crank to the 366, the piston would be big money and you still have the intake valve shrouding issue.    Now if you're building a rat rod or tow vehicle....go for it.  But, Don't don't don't do it as a performance effort.

Ok.  Mystery solved. Turns out the motor was a 350 out of a school bus. It has been bored 60 over which made it a 360 cubic inch small block. Guess I got confused an identifying it as a 366 big block. Turns out the motor needed work. Passed on it.

So I finally made a Command Decision. Found a tired 99 Vortec headed motor out of a Tahoe. Gonna just bite the bullet and freshen this motor as it apparently had some blow by. Once I clean everything up probably throw in some flat tops and new bearings and a roller cam if I can find one reasonable and call it a day. Have a cheap intake so converting to carb. I figure I will be able to build the motor  for under 500 bucks which is about all I have left in my budget . Will keep you guys posted.

Ovid_and_Flem said:

Ok.  Mystery solved. Turns out the motor was a 350 out of a school bus. It has been bored 60 over which made it a 360 cubic inch small block. Guess I got confused an identifying it as a 366 big block. Turns out the motor needed work. Passed on it.

Don't worry about it.  I'm sure everyone with knowledge of the tall deck big blocks had fun informing, and lots of people now have a tiny corner of their brain clogged with that useless information.  That's almost always good!

GTXVette said:

 

 

so just so they know,  on a 350 chebby 4.00 bore a  .030 over bore  is good for about a big 3 cubes, some may say 4 cubes but that's the high side

About 5 1/4

The posts by Atilla on thirdgen.org used to include a tutorial for basic exhaust side porting on the iron Vortec heads. Pictures were removed but there are some minor improvement areas on the exhaust side IIRC. You might also find part numbers for the correct springs to use. Try to use OEM stock roller rockers or stock stamped ones, I'd stay away from cheapo roller rockers. You have to make sure that the pushrods that you use are the correct length after all the machining and everything. Better to make a detailed parts list and review it a few times instead of ordering one thing at a time.