I know this is not as old as a lot of you guys like, but does any one have a copy of the engine specs they can send me? I cant find a service manual any where at the stores around here. Im trying to get the tolereances for the motor. Like for the crank and cylinders and stuff for a rebuild. Thanks
go to www.cl***icalpontiac.com. they will have everything you need. or www.performanceyears.com, both are pontiac specific sites. happy hunting!
this book is usually available in bookstores, parts stores, and public libraries... http://www.gohastings.com/Catalog/Item/Item.asp?prodid=19945968
I built a few of those in my lifetime, and I still have one here albeit not being used for anything at the time. Basically that was Pontiac's grocery getter 2-bbl engine, rated at 250 HP in 1970, with 8.8:1 CR There also was an "HO" version in 1968-69, it used the big valve heads from the GTO, and was rated at 330 HP, with approx. 10:1 CR specs- bore size 3.88"- stroke 3.75"- 3" main journal- 2.25" rod journal- 6.625" rod length- came with nodular iron "armasteel" cast rods- cast crank- press in studs up to 1972- 1973 up had screw in studs- small valves unless you have the HO version, which most likely you don't cuz they were rare- but the HO version will have the big 2.11/1.77 valves and screw in studs all the heads have hardened guide plates FWIW, I took the stock 350-2bbl 250HP engine in a 1970 Firebird, put a '69 Grand Prix intake/carb on it Qjet, a bigger cam, and cheap 3-tube headers- with a TH350 trans the car did 140 mph on I-81 highway one night, and would have buried the 160 mph speedo if I stayed in it- car had 2.73 gears clearances- shoot for .002"-003" on the mains and rods, and go with the piston makers spec on piston/bore clearance. I highly advise replacing the cast rods with forged rods. The cast crank is plenty strong will take 650 HP for years. question- if you want to build a Poncho, why the 350 ? The 400 is a mighty bit better engine, same motor but with a 4.120" bore. The 400 will run rings around the 350. I took the soft plugs out of a Poncho 350, measured water jacket clearance, those blocks have thick walls, you can take the 350 Poncho to 4" bore size- and drop an aftermarket crank 4.25" stroke in it- and make a 427" from the 350 sonic check for core shift first.
Sounds like my kinda people. I've got one in my 65 Ford pickemup. It runs like a champ, course I'm not askin it to do more then just RUN. Besides, when ya got your bible on the bench seat and your "solo gator" painted on the tail gate next to the cacti.......who wants to keep up with traffic anyways? In 1971 that motor was put into Le Mans and Firebirds. It came with a 2 barrel carb and produced 250 ponies at 4400 rpm. Your lookin at 350 for torque with a compression ratio of 8.0:1. They lost 5 ponies from 70-71. Use it if ya got it. Brandy
sonic check it for core shift? don't you mean bore thickness? and I ***ume you meant hardened valve seats, and also have guide plates-duh,ALL PONTIACS HAVE THOSE! as far as the rods are concerned, pontiacs only use one size rod. and they all pretty much kick ***. no need to change them unless you are going to do something exotic like build a stroker, and in that case you should probably build a 462 or a 515. but it sounds like you are going for pretty much stock. use what you got, and if you are that worried about rods, buy some nice light pistons and call it a day
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