305 Parts recommendation/for sale

[Rob Liebbe]

This might sound strange, but I am looking to slightly improve the 307 that is in my 70 Chevelle.

The camshafts in these engines are known to have high wear causing lower performance and high fuel consumption and likely needing replacing by 50,000 miles. My car has these issues at its current 37,000 original miles.

I'm thinking about 305 heads for a compression increase and a cam that has good idle and makes decent torque. I already dumped the two barrel carb and iron intake for a 600 cfm spread-bore Holley on an Edlebrock Performer alum intake.

I know, I know, upgrade to a 350, but the car is a low mileage "family heirloom" with a Powerglide and 3.00 (I think ) rear gears. I just want to make it drive a little better and on a budget.

Any thoughts from the 305 gurus?

Rob Liebbe

[Storm Trooper]

I have the 305 that came out of my race car, it needs to be rebuilt but the heads were good in shape.

[BryanL]

Read this link from an engine buddy of my dads. I think they said the 307 can be similar to a 283 with a head/cam swap and should run pretty decent. But then you also might need to change the torque converter. Checking the rear gear ratio and going lower is going to really help the takeoff with a small engine. Then if you want to do a lot of highway driving put in an overdrive. I don't remember the dimensions of a PG but a 200r4 is the same length as a TH350.

For not much more money I would consider getting a whole motor. I understand the sentimental low mileage but consider pulling the original motor out to save it and put in a better motor. Heads/cam is probably going to run you what $500 and a lot of labor which you still have a worn out 307. I bet you can find a decent motor complete for $500-you just need a long block.

Here is a link the guy sent me to read about some 307 changes.
http://www.chevelles.com/forums/18-engine/214329-305-ho-307-a.html#/topics/214329

[Supercharged111]

The Vortec truck motors are dirt cheap and run circles around the older stuff. Still GenI too no retrofitting, just need a compatible intake. They use more modern gaskets too and leak a lot less.They come as a 305 or 350. IMO once you yank those garbage heads the originalness is gone so why keep the 307 in there?

[Rob Liebbe]

The Vortec truck motors are dirt cheap and run circles around the older stuff. Still GenI too no retrofitting, just need a compatible intake. They use more modern gaskets too and leak a lot less.They come as a 305 or 350. IMO once you yank those garbage heads the originalness is gone so why keep the 307 in there?

OK - what year did the Vortec 305/350's go into the trucks? And what years use the old style intake manifolds?

[Storm Trooper]

OK - what year did the Vortec 305/350's go into the trucks? And what years use the old style intake manifolds?

96 was the first year for the 5.7L and 5.0L Vortec CPFI small block V8s

[Supercharged111]

OK - what year did the Vortec 305/350's go into the trucks? And what years use the old style intake manifolds?

96-98 (99 as the classic, not very common) in the half tons, they lived until 2000 in the 8 lug chassis, and until 2002 in the vans. You can get intakes pretty cheap on Summit too.

[marshall_mosty]

Regarding the PG to 200R4, there are conversions available. That is what I'm planning on for my '57 to get rid of the "glide".

[Rob Liebbe]

Regarding the PG to 200R4, there are conversions available. That is what I'm planning on for my '57 to get rid of the "glide".

Th Powerglide is neat in a nostalgic/unique kind of way with only one shift but first gear is more like a second gear an TH350 of 200R4.

[BryanL]

For off the line pep the biggest change would probably be the transmission or rear gear. 3.00 and a PG will sure take awhile before the revs get up much and by that time you are already going the speed limit when it shifts. 700r4 has a pretty low first gear.

[Supercharged111]

How long was the PG in production? I figured once the TH350 came out they'd have axed the PG, but it seems they were in production at the same time?