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Chevy 307 - POB 307?

2K views 13 replies 7 participants last post by  El C 
#1 ·
Here´s the problem.
One choise for 1972 El Camino was 307.
Chevy discontinued 307 at -73 (am I right?), but Buick and Oldsmobile (mayby also Pontiac) uset 307´s much later.

These are not the same engine, are they?

My El C has a THM200c transmission with Chevy bolt pattern (now with Chevy 250 inline 6 engine) and when I see a 307 it´s with the BOP bolt pattern, so it doesn´t fit.

If they are not the same engine, should I go with later Chevy 305, that fits?

Also, which is better for a daily driver?
 
#5 ·
poncho62 said:
Why not find a 350?....probably same cost and easier to find.......
Reason 1
I live in Finland where 350 is the most desired engine for a GM. That´s why they are pretty expensive ans not so easy to find.
Reason 2
My El C has a thm200c transmission and I need to keep it. 350 might be a bit too much for it.
Reason 3
If I were to put on a 350 I would also need to change brakes and suspension parts and I´m not in the situation to do that.

So, I´ll need to choose between 305 and 307, just trying to choose wisely...
 
#7 ·
El C said:
Reason 1
I live in Finland where 350 is the most desired engine for a GM. That´s why they are pretty expensive ans not so easy to find.
Reason 2
My El C has a thm200c transmission and I need to keep it. 350 might be a bit too much for it.
Reason 3
If I were to put on a 350 I would also need to change brakes and suspension parts and I´m not in the situation to do that.

So, I´ll need to choose between 305 and 307, just trying to choose wisely...
OK....didn't notice the Finland thing.........I wouldn't discount a 305....They are a good engine and tons of them around........The only thing I have ever heard bad about them was some of the cams used to go flat.......easy fix.

I don't understand your reasoning on the suspension and brakes....a 350 weighs exactly the same as a 305/307
 
#9 ·
El C said:
Here?s the problem.
One choise for 1972 El Camino was 307.
Chevy discontinued 307 at -73 (am I right?), but Buick and Oldsmobile (mayby also Pontiac) uset 307?s much later.

These are not the same engine, are they?

My El C has a THM200c transmission with Chevy bolt pattern (now with Chevy 250 inline 6 engine) and when I see a 307 it?s with the BOP bolt pattern, so it doesn?t fit.

If they are not the same engine, should I go with later Chevy 305, that fits?

Also, which is better for a daily driver?
BOP 307s are not the same as Chevy 307s but they can be adapted with commercially available adapters from the U.S.

A Chevy 305 is also a bolt in against your existing mounts, radiator, and Chevy trans.

A 350 would be nice and TH200s can be built to live with it again you need parts or a tranny probably from the U.S.

Given you already have a 250 inline 6; another interesting swap choice if you can find one is the 292 Chevy 6, it's found in trucks. The block is a bit taller than the 250 so you'd need to check that the hood closes, or put a bubble in it if it doesn't. The GM inlines are well supported with aftermarket hot rod parts and building a 292 that will embarrass a moderate small block V8, isn't too hard to accomplish and a lot of fun to do. The 292 passenger side mount is located differently, you'll have to take it from the truck or cut an adapter from some steel plate, no biggie, hand tool job if you don't have a welder or mill.

Bogie
 
#10 ·
A guy I knew that`s now deceased was a pulp wooder in his younger days. He was a solid Ford fanitic. But, he would be very quick to say, "the best Chevy engine ever made was the 292 straight 6. Great torque. We beat those engines to death on pulp wood trails and they never once grunted"
 
#11 ·
292 straight 6, kinda interesting...
It´s just the sound of a v8 that I would still be missing. :)

To Bogie, you said;
BOP 307s are not the same as Chevy 307s but they can be adapted with commercially available adapters from the U.S.

Yes I know.
But it still isn´t the Chevy engine. These BOP engines that we have here are almost all from -80s cars and wagons. Those engines are pretty poor on power. Older Chevy 307 from early -70s were more powerful.
Or am I wrong again... :(
 
#13 ·
I wouldnt totally cancel out a 305 if you can find one. If your not planning on dragging the elky ill definitly not overlook one. All the 305's ive ever had have been perfect for daily drving and little street performance. Usually perfect 305's are taken out of perfect running vehicles cause they were scrapped for a 350's. I have a 80's model with a very mild cam and she acts nice on the street but when I get in her hold on. If you can find a 350 perfect but dont overlook a nice sleeper 305
 
#14 ·
SSedan64 said:
I'm not sure what the BOP 307ci were rated at. Untill 72 the Chevy 307 was rated about 200-215HP & 285-320TQ.>> http://www.chevytech.com/1c1.html after 72 the compression and cam sized dropped along with very poor performance.
Yeah, I know.
And I have a -72 El Camino, so It would be nice to have an engine that could have been there from the beginning...

I haven´t forgotten the 305, it´s still the most obvious choice for me.
 
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