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05-06-2020, 11:58 AM | #21 |
Senior Member
Join Date: May 2010
Location: Chester Vt
Posts: 8,860
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Re: Valve Spring Shim Question
I wonder how many people here have heard a flathed float it's valves? SBC?, any other engine
In the early 60's the owner of our stock car bought an engine with an Isky 404 cam. It also had compound valve springs installed with 135 Lbs on the seat. We ran the enngine for several races before the season ended, I removed the eengine and took it homee with me becaused it used allot of oil. I removed the valves as well, whicj was quite an issue. When I returned the cam I used LZ springa with 65 lbs on the seat, We went racing the next year and the engine ran fine, but at the end of the straight a ways you could jear alittlr pop pop but the engine had excessive piston clearance and was still using oil. so I built another engine with a 499jr cam which ran much better.. Afew years later I discovered not many used the 404 cam and most used the 400 jr, AS tires and other legal modifications became available, the speeds increased drimaiticly . Improved carburation and porting larger carb and hiher gears we had dropped the track time from 22 secs in 64 to 17 secs in 68 by the end of the flathead eara track time dropped to 16 wit h the 3400 weight rule. I had switched to the sig Erson D410 cam by then which was much better than the 400 jr. I'v contacted Erson and they nolonger make that cam any more. I think it was a modern design base on the 400jr. Erson worked for Isky in the early days. The little 358's were turning well over 5k. I still have the cam and I think it would be a vast improvemt of ver what's avaolable today. Unfortunately, in my old age I've stopped thinking of making more power, but better fuel econmy. |
05-06-2020, 12:00 PM | #22 |
Senior Member
Join Date: May 2010
Location: Chester Vt
Posts: 8,860
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Re: Valve Spring Shim Question
Mtt
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05-06-2020, 12:02 PM | #23 |
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Join Date: Nov 2015
Posts: 89
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Re: Valve Spring Shim Question
That's neat information Ron! Fuel economy is a far less slippery slope than big horsepower!
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