307 input needed

[Bagd72Chevy]

My 67 has a 307 that is not original. From the numbers I have a 307 from a 1968 B-Body backed with a TH400. It had a 70's era smog intake with a mismatched 2 barrel. I installed a late 60's aluminum corvette intake, quad adapter and edelbrock 600. It runs ok, but seemed low on power. When I did the intake I noticed that the valley was super super clean. Same for the heads, no buildup up top. Well 300ish miles into me owning it and the cam is shot. Starting backfiring really bad yesterday, pulled the covers and had some loose rockers. I adjusted the rockers and I've got a few not moving.

So, how much lift can I run on stock heads if I just put a cam and lifters in it? Any recommendations on cam? I have 3.73 gears on 29" tires, TH400, unknown stall (seems stockish)

I was looking at the summit 270 cam kit. .398/.421 lift but could I go bigger?

[hamjet]

Make sure you have oil pressure, maybe the lifters aren't pumping up...

[mechanicalman]

Originally Posted by Bagd72Chevy

My 67 has a 307 that is not original. From the numbers I have a 307 from a 1968 B-Body backed with a TH400. It had a 70's era smog intake with a mismatched 2 barrel. I installed a late 60's aluminum corvette intake, quad adapter and edelbrock 600. It runs ok, but seemed low on power. When I did the intake I noticed that the valley was super super clean. Same for the heads, no buildup up top. Well 300ish miles into me owning it and the cam is shot. Starting backfiring really bad yesterday, pulled the covers and had some loose rockers. I adjusted the rockers and I've got a few not moving.

So, how much lift can I run on stock heads if I just put a cam and lifters in it? Any recommendations on cam? I have 3.73 gears on 29" tires, TH400, unknown stall (seems stockish)

I was looking at the summit 270 cam kit. .398/.421 lift but could I go bigger?

Hard to account for that old of an engine to be so clean, unless it was recently rebuilt, even harder to account for the condition of the valvesprings. That being said, I think I'd put back a stock cam. If you want to upgrade the cam, you can go up to about .450" lift on good stock springs, so you should put in some new springs (cheap) and replace the valve seals.
http://www.competitionproducts.com/H.../#.VGFgQE10xdg
http://www.competitionproducts.com/V.../#.VGFgkU10xdg

You might have a hard time getting the old lifters out if they formed a lip on the crown of the lifter. Twisting them may get them out, but it will leave terrible gashes in the lifter bore that will cause the next cam to fail if you don't hone them out, and honing them is not a good idea because you are removing metal from a lifter bore that is already worn. So, with a few lifters not moving, and likely some others worn, you probably have a lot of metal sitting in the bottom of the pan and in the oil filter. So, remove the pan and clean it out.

Best way to remove lifters is to remove the oil pan first anyway, then pull the lifters up just enough to stick, pull the cam out and let them fall out the bottom. If you don't pull the pan, then you will likely create an oil leak at the front of the pan, and end up hacking up the front timing cover to get it back in. And a rear main seal while the pan is off, and a new plastic sleeve on the oil pump drive shaft if it isn't new. Get you one of those nice 1 piece oil pan gaskets.
http://www.summitracing.com/parts/fe.../applications/

Whatever hydraulic flat tappet cam you choose, use these lifters:
http://www.ebay.com/itm/SBC-DELPHI-L...662d12&vxp=mtr

New oil, filter, break-in lube and break-in procedure for both the new cam and new springs if you use them.

PM me if you need any more help.

[mechanicalman]

Originally Posted by Bagd72Chevy

My 67 has a 307 that is not original. From the numbers I have a 307 from a 1968 B-Body backed with a TH400. It had a 70's era smog intake with a mismatched 2 barrel. I installed a late 60's aluminum corvette intake, quad adapter and edelbrock 600. It runs ok, but seemed low on power. When I did the intake I noticed that the valley was super super clean. Same for the heads, no buildup up top. Well 300ish miles into me owning it and the cam is shot. Starting backfiring really bad yesterday, pulled the covers and had some loose rockers. I adjusted the rockers and I've got a few not moving.

So, how much lift can I run on stock heads if I just put a cam and lifters in it? Any recommendations on cam? I have 3.73 gears on 29" tires, TH400, unknown stall (seems stockish)

I was looking at the summit 270 cam kit. .398/.421 lift but could I go bigger?

With new springs, this cam.
http://www.summitracing.com/parts/su...make/chevrolet

[cdrummer316]

No matter what cam you run it's necessary to run an oil with high zinc. Flat tappet camshafts need zinc in the oil that today's oil doesn't have. I personally use Joe Gibbs break in oil to break in the new camshaft change oil and filter then I use their hot rod oil. There other brands but this what I've been using and never had an issue. And if your lifters failed after 300 miles, metal is now in your oil. Not good. Trust me it's happened to me.

[Redline novdog]

at this point I would buy the cheapest cam and lifters you can find. Use good phosphate/zinc break in oil and look for another small block. if all that cam/lifter metal has run through the cam/rod/main brgs. It is a matter of time before the bearings are toast!

[Warrens69GMC]

http://www.summitracing.com/parts/sum-k1102

[72bowtiestepper]

Have you considered a new crate 350 engine ? Might just save you time, money & aggrevation. Jegs sells them on Ebay some times for around $1300 with FREE shipping.