While enjoying a sunday drive my motor started to chatter, without any prior warning. Being three miles from my house, I tried to make it home, started to blow white smoke and the engine locked up and shut down. After careful examination I noticed the head gasket had blown. The oil pump must have malfunctioned as well and burned out the engine. So much for non-working idiot lights. Next time I will comvert to gauges. Question: I would like to replace the blown original 307 with a 350/270HP motor. I have been informed that a re-build, in this case, would not be practicle. The car has a 350TH trans. The car is an a/c vehicle. Will the 350 bolt up to my trans, and have the space and mounting areas for the a/c option? What do I need to be aware of when ordering my new motor. Any insight or comments would be greatly appreciated. Dennis

Sorry to hear about your motor. Been there, done that...

A good way to go is with a GM crate motor. They range from standard 350's to HP 502's
This way you have a new, warranteed engine and you can't rebuild a used engine for the cost of the new crate 350.
A small block is a small block. The 350 will drop right in.

Good luck,


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Bill Taylor
TC Gold Member #73
www.chevelles.com/showroom/BillTSS70-2 (http://www.chevelles.com/showroom/BillTSS70-2)
www.chevelles.com/showroom/leaves2 (http://www.chevelles.com/showroom/leaves2)

I recently replaced my 307 with essentially that HP 350. You should have no trouble with the room, trans, AC, etc. since the size of the engine is the same. The intake and carb can also be used but if you can swing it, you might look into a better intake and a 4B carb. A 600 cfm Edlebrock or Holly would be good for that motor (~270 HP).

I installed an ATK engine and could not be happier! They can be seen at www.atk-engines.com

Good luck and sorry about the demise of the 307.

Bob

Dennis,sorry to here about Your misfortune of the 307, but I would like to add,Im am far from being a really good mechanic,(I have a ton to learn). I did drop a 350 crate motor in a 82 chevy PU apx10 yrs ago,and some 180,000 miles to date. The moter still runs very good and uses little oil, I have never done anything extra to the motor ,,, except change the oil every 3,000 to 3,500 miles,and a minor tune up ocasionally. So what I am trying to say is if You dont wana build Your own motor up ,,I think a crate motor from (chevrolet) IS a really good way to go in the long run. just My thoughts ,, Good Luck Tintop55

Dennis, let me answer your question as throughly as possable. Your 307 is a small block chevy (SBC). A chevy 350 is also a SBC. All SBCs are the same dimensions externaly. All of the brackets you have on the 307 (A/C, alternator,etc) will bolt up to the 350. Also the exaust manifolds will bolt up. All chevy th350 trans will bolt up to any SBC. Things I will advise you on, make sure you get these gauges: oil pressure & engine temp. These 2 won't save you from the same problem but, with proper maitenece, can ensure that your new motor will have a long and happy life. Any other questions?

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Joe Y.
68 malibu
Bloomington/Normal, IL

Only thing I'd add is the dipstick on 1980 (?) and newer engines is on the pass. side of the engine, check clearance with AC housing if you get this type. And on 1988 and newer engines the rear crank flange is different and will require a flywheel/flexplate for the newer engine. Not a big deal. tom

Thank you for your advice. I have looked into Jasper motors And will look into the GM crate motor next. Jasper offers a 350 with 200,250,300, 325, and 350 HP. Prices range from $1400.-$2500. If I go with the 350HP I will have to change the converter. I will definitely convert to gauges. Dennis