Quote:
Originally Posted by OE Espo
Helping someone work on a 70 Lemans Originally equipped with 350 2Bbl. Have build-sheet and under 40k original miles.
Doing some research probably (guessing here) has a 254 camshaft .375 int .410 exh. Has No11 heads. Believe its a 2.78 open rear.
Want to wake it up some this winter but probably in stages.
1. Winter plan replace 11 heads with 13 (have them). getting them cleaned up. they dont have springs OR rockets in them. considering keeping cam now and using 1.65 rockers. no port mods. hoping block is chamfered for larger valves and just increasing ratio that we wont have any valve interference.
2. Add 68-72 iron intake (have)
3) Add quadrajet
Thinking these mods alone should get better seat of the pants feel.
Future considering 068 cam, 3.23 rear posi Want something for highway trips
Should i get heads milled to more like 350 HO #48 heads. had one in my car it ran great. if so to what cc?
other camshaft recommendations?
rear gear recommendations?
thanks
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We have two ’69 350 HO cars, a 4-spd Firebird and a Custom S with a TH400. The Firebird’s 350 HO has the 068 cam and the Custom S (Lemans in 1970) has the 067 cam. They are both strong running cars with easy 14 second quarter mile times (low 14’s for the Bird, mid 14’s for the Custom S - the Firebird has a 300 lb. weight advantage). They both have their original 3.55 rear ends.
I like what you’re planning with the #13 heads (75 – 78 cc’s) with the factory cast iron intake and a Q-jet carb (find a 7040264). Don't cut them more than you have to just ensure they are flat and true. This will keep your compression in the mid-9's and run fine on 93 fuel). The 3.23 (with posi) is a great gear for in-town and highway driving. I would suggest the 067 cam (with decent springs) with the TH350 trans and the stock convertor. I wouldn’t go with the 1.65 rockers arms. Obviously, a good dual exhaust system is part of the power equation. If you can change the oil pump to the 60 lb. version would be great. The bearings will be fine if you keep the revs under 5200 rpm and use a good grade of oil like Brad Penn, Lucas, or Valvoline VR-1. You won’t need to shift any higher with an 067 spec cam anyway (the Summit 2800 is a good choice too). It’ll be quicker than you think.
Dennis