will a late 70's 305 block swap with my 92 305 block? are they the same? if not what is the difference?thanks

 

no it will not. The 92 block has provisions for a roller cam and came with one. It also has a one piece rear main seal and an internally balanced crankshaft. The late 70s 305 has none of these.

 

Well, that's a little over stated.

Let's list the differences:

As mentioned, rear main seal type. You need to use a flexplate that is of the right type for the rear main seal type. But, that's all you need to do.

Roller cam - yes, that's a difference, but won't prevent the engine from "fitting". Just use a cam of the proper type (if you're even going to change the cam).

Heads: Depending upon how much of this '70's engine you're getting, the early heads have perimeter valve cover bolts, non-self-aligning rockers, and all of the intake bolts are at the same angle. The later heads have center bolt valve covers, need self-aligning rockers, and the center two intake mount bolts are at 72 degrees instead of 90 like the rest.

Depending upon how late in the '70's this engine was, the dipstick may be on the driver's side rather than on the passenger side like all 3rd gens were.

None of these things will keep the engine from "fitting" into the car, to your transmission, or with your induction/sensors/accessories, etc. Only possible exception is if the dipstick is on the driver's side, you will have difficulty getting the tube around the factory exhaust manifolds.

None of this addresses whether you "should" try to put a late '70's 305 into a '92 car. Personally, I'd pass on it and go for a 350 or at least a TPI-type '87-later 305, even if keeping the TBI. But, I suppose you're getting this engine for free, and you've done something to kill your original engine, right?

 

Oh, as far as being "internally balanced", technically the earlier engine is, and the later engine is partially. That's addressed by having the right type of flexplate, though. No biggie.

 

so i cant use the block to build and be smog leagel in california

 

Depends upon the level of "legal".

You could build it to meet the sniffer requirements. Technically, though, you aren't allowed to put older stuff in a given year chassis. If the inspector goes ****, knows enough to know the dipstick is on the wrong side, and starts checking casting #'s, you're toast.

What exactly are you trying to accomplish?

 

well i want to build an engine mine in my car now has 175000 miles on it and is getting pretty weak. so i have a complete 305 engine with heads and every thing i know the heads wont work so i was wondering if the block would and a could build on that.

 

and if i found a 350 and built that and put a tbi on it would it still pass california emessions i was told by people here that there 350 passes as a 305 that the smog shop doesnt notice

 

A 350 would be a better idea. Not "simple" or a "bolt-in", necessarily. But, as long as it looks like the 305, you shouldn't have any trouble getting past the sniffer.

 

He asked if the blocks will swap.. and no they won't. Now a complete motor will bolt right in aside from the dipstick and needing to take a dremel to the center bolt holes on the intake. Now for california emission raping the motor will not work. Like 57bird said it in not legal to swap an older engine into a car in cali. A 350 will pass 305 emissions though. A 350 can pass 6cyl emissions so passing the sniffer will not be a problem. The underhood inspection is all that will be trouble. Just find a 350 and swap it in.

 

so what year block could i use? are the 87-92 the same? and if so could i use like a 88?

 

Is there any particular reason you keep saying "block"?

My responses addressed "engines", Cronic took exception to that because you said "block" originally, but later you said you had the whole engine.

Do you mean bare block (i.e., the casting), shortblock, longblock, full engine - which?

Just to be clear...


(BTW, '87-up 305 "blocks" are all basically the same.)

(And just for the record, 305 and 350 blocks are different, even though they bolt into the car exactly the same.)

 

im saying "block" because i want to build a engine. i have a 70's long block out of some pontiac but i dont want to use those heads or anything off it i just want the block to build on. if i found a 87 and up long block out of a trans am or z28 i would use that but if i found a lo3 engine like i have now i would want to use just the block to build on.

now what year blocks or engines can i use 87-? and i need to beable to pass emissions. thanks

 

If you get an **** inspector (like one that had a fight with his wife last night, and is looking to "get" somebody), you'll have to have a block that is '92-up vintage.

If you draw an inspector that just wants to verify that you have the required equipment and the engine burns clean enough, you can easily pass with the '70's block.

BTW, technically the 350 is not legal. You will only pass if you get Inspector #2.

 

ok thanks