is this a 350 or a 305?

[jrruta]

i bought a 1987 chevy half ton truck 155,000 miles on it, i was told when i bought it that it had a chevy 305 engine in it

the exhaust needed replaced so i bought a pipe from the CAT, to the muffler a muffler and a tail pipe, everything fit as planned except for the cat to muffler pipe, so i cut here and there and made it fit because it was too long.

later I checked the VIN # which said that the truck had a 350. this truck has a 700r4 tranny with 3.08 gears in the rear. I don't get to drive too many trucks and am not sure how to identify this engine seeing as how the 305 and the 350 are the same block. Can someone give me some advice?

[Fast68Chevy]

the emissions lable sticker underhood either on top of rad support fan shroud or on one of the inner fender liners on top side will have 5.0L or 5.7L in top RH corner of the label

also look in glovebox for the SPID ID label and it will have engine code, begins with L L61, L03, or L05, or L31 or similar


also check the harmonic balancer and see how wide it is,
usually widest and 7" diameter= 305 and narrower but taller(8" diameter) is 350

also there is a flat machined sztamping pad about 2" wide almost, just above the timing cover and under alternator area on the pass side of engine basically, get flashlight and long screwdriver and rag and maybe some carb cleaner and clean it off and get the thre uppercase prefix letters stamped into it


good luck

[fluffytx1]

As a rule of thumb but not in all cases see where the oil dip stick tube is. passanger side 305. drivers side 350. bud to know for shure run the #'s

[Fast68Chevy]

as far as i have ever seen all 80-up engiens have long stikc on pass side

good luck

[73GMC]

Fast68 is correct. 1979 was last year chevy small block had oil dipstick on driver side. 1980 started passenger side.

back side of motor on driver side should have the motor #. any rebuild shop or book should have the numbers listed.

of course, if was ever rebuilt, you wouldn't know if it was bored out. the only true way to know would be to dismantle and check bore size and crank size............

[Fast68Chevy]

i wish i knew why ppl think that there were still engines with driver side sticks after 79,

odd...

thanks

[chevroletrucks]

The best way to tell.. is to get the numbers off the block which are located behing the back of the intake where the block meets the bell-housing. Most of the time these are hard to read due to grease and grime so take a can of brake parts cleaner (with a straw on it) and spray the area down and wipe it with a rag. Then call your local machine shop and ask them,most machine shops will run the numbers for you no problem.

[Fast68Chevy]

easier to get the stamping code off the front flat stamping code on front of block and look it up at nastyz28.com or call dealership parts counter, that is lots more accurate than the casting code off rear of block because many appications and years used same casting, 3970010 casting is just one of tens of examples of this,.

good luck

[gchemist]

Considering its a 87 and FI, I would bet it's a 350. GM brought back the 350 as standard engine because of FI.

[70sChevys]

Here's what I did...get the number from the back of the block (right behind the valve cover on the driver's side)...be careful as 3's and 8's and 0's are very close when dirty. Then pop the driver's valve cover and read the number toward the front of the head. Get both those and go to mortec.com or nastyz28.com. You hopefully will find they match, but it's very common for some moronic reason to find 305 heads on a 350 (cheapo rebuilder or idiot). Mine was found to have this strange combo...still not sure why anyone would do this although I hear some circle track racers do it for added compression.

[cjwilson99]

Just crawl underneath the truck and look that the bolts holding the starter on the engine. If the bolts are perpendicular (straight across from each other) to the drive line then its a 305. If they are staggered its a 350, or 400.

[Fast68Chevy]

Originally posted by cjwilson99
Just crawl underneath the truck and look that the bolts holding the starter on the engine. If the bolts are perpendicular (straight across from each other) to the drive line then its a 305. If they are staggered its a 350, or 400.

that only works for '80's 305's in the camaros and regals and cutlasses and montes and firebirds and some trucks, IE the oens with ESC copntrol systems and oddball emissions exh manifolds

not al 305 have the 153 tooth plate/wheel, most all 305 in 75-79 are 168 tooth wheel or plate just like any other engine, and not all 400 are 168 tooth either.

and to identify an engine you shouldnt be looking at heads anyways, casting number of block is very vague
the front pad stamping code is very exact and will telly you year and what vehicle was installed into and with what tranny behind it even,.

get the front machined pad stamping suffix code letters off front of engine on pass side top and post them here or call dealership parts counter


good luck

[cjwilson99]

Thanks Fast68. I learned something new. I really like these boards. So much info.