Talking compression?

[SgtLee511]

Any of yall, out there still running high compression pistons, Im unfortunatly built this engine in the late 80's, at a time when we were all looking at going low compression. I didnt, I'm reading these posts about camshaft swaps all of which are going in these lower compression motors, I havent checked my compression lately as the car sat since 1993. It originally had the DC purple shaft, swapped it about 92 for a stock cam. Most of the small block post are talking well about hughes camshafts and our big block brothers dont seem to support hughes that well. How do yall feel about a whiplash camshaft in the higher compression motor. Yea it pings sometimes. :violent1:I have a 70 stock motor, edelbrock air gap, edelbrock 725 cfm carb, 3:23s to be lowered. Im having to go back in an put new valve seals in as it has a tint of blue from the pipes, so Id like to beef up the 340 with a new cam and springs, without having to do further modifications.

 

[gtsdude]

I just put an MP .597/288 hydraulic cam to run in my 340. It is a circle track cam. The engine has the factory replacement advertised 10.5-1 pistons in it, but actual compression is at 9.5-1. Here is where I got it, has some good deals on small block cams. I got the cam because it used the factory 340 springs and I don't have to cut down the guides.

http://marketplaceadvisor.channelad...&c=411768&search_text=&srch=1369038661&page=1

 

[Mo-Par]

Pull the plugs and do a compression test.
Otherwise you are just guessing until then and there really is no way of making a good cam selection.

 

[duster360]

The one I just pulled still had the factory 10.5:1 slugs in it. But as mentioned earlier the compression was actually closer to 9.5. No pinging at a all. I ran the blue Felpro head gaskets which are way thicker than the factory steel shims.

 

[greenswinger]

Im kinda in the same situation. 360 isn't built yet but I have some KB191s. Talked to UEM on the phone and they reassured me I can mill the dome to the same height as the quench pads for 10.5:1. Looking real hard at Comps big mutha thumpr. The duration would drop dynamic compression enough to minimize or eliminate ping on 93octane I think. Any input??