Valve Seat Set
Valve Seat Set
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Lead Additive chevy In what year you start using hardened valve seats for unleaded fuel use?
I just installed a 1971 Chevy 307 in my Jeep Wrangler children. Whichever engineer who designed a Jeep with a 2.5L 4 banger ... obviously not owned one or led one. Because life Me, I do not remember what year it changed to harden chevy valve seats for unleaded fuel. I didn't pull the heads, but I could see that it is a flat engine superior compression and probabaly 9-1. I set the schedule a little late to stop the ping to find out what type of fuel you need to plan for. With I have a 1971 engine to run a lead additive? Thanks .... Kelly, but I need a lead additive? 4 and 12 BTDC total time. I have my 406 in total 40 BdB: I know what I have ......
It was 1971. I put over 200,000 miles in a 71 Monte Carlo 350 running 85 octane unleaded with no valve problems. The 10% ethanol in the gas does not bother either. You can run an additive but not make any difference to the engine. "By 1971, GM ordered all divisions design their engines to operate regular lower octane, low lead or unleaded gasoline due to the strengthening of emission requirements and in anticipation of the catalysts used in 1975 models later, requiring the use of unleaded fuel. To allow use of lower octane fuels, all engines compression appears in low percentages (9-1 and smaller; well below the 10.25-11.25 to 1 range on high performance engines from 1970 and earlier). "Source (s): http:// en.wikipedia.org / wiki / Chevrolet_C ...