Aaronz28 Posted March 1, 2016 Share Posted March 1, 2016 My Ls5 has had the compression dropped to 9.25:1 with the stock LS5 heads Curious to know your thoughts..... My plan... Have a set of small chamber 67 bbc oval port heads.will have them fittted with large vlaves and open up the exhausr side some. Should yield 10.5:1 Gonna run a Ls6/L72 solid lifter cam (have an NOS one on the shelf) Use the 68-69 oval port 3x2 holley seteup from the 400hp 427 Corvette motor. Car has a th400 and was factory ordered with. 3.31s Might consider going to 3.73 (or 4.10 and the gear vendors overdrive if its too doggy below 2500) I really really really wanna run the Gardner Chevelle Chambered Exhaust (had it on my 69Z). Was loud but unmistakeable. I know i could probably do bettter with headers and a mandrel bent free flow 2.5" system but i really love the notion of using some of the best GM street HIPO parts that were available le at the time. 1 Quote Link to comment Share on other sites More sharing options...
dbreese Posted March 4, 2016 Share Posted March 4, 2016 Looks like a good set up to me. If you can keep your static compression around 10.5 you should be good on pump premium (93 non-ethanol if you can get it). Dial in a conservative initial/advance and total curve on the timing and sneak up to what the car likes. If you plan on pulling the engine and when things are done, if you have a engine dyno service in your area this can be a invaluable tuning device in getting the most out of your engine combo. Since you are keeping the factory exhaust manifolds I would get in touch with someone who is knowledgeable in extrude honing. All the muscle car guys who run the FAST (Factory Appearing Stock Tire) racing class do this and it is worth some hp. It will be a torque monster for sure. If you are just going to cruise I would say 3.31 would be a good gear but 3.73 would be way fun. With the cam specs .520 in 240 dur @ .050 on the intake side and I think about the same the ex side I would look into a custom converter. Talk to any good converter company and they will talk you through it. If you have a engine dyno sheet that is a great help to them when building the converter. I did this with mine and they got it the first time around. I know I'm a s/b guy but it looks like ya have got a good plan and a trip-power setup on a Monte would look awesome. I'm sure the B/B gurus will chime. David 1 Quote Link to comment Share on other sites More sharing options...
stangeba Posted March 4, 2016 Share Posted March 4, 2016 What is your goal? I'm a pure stock, from the factory person, everyone is different. Bruce Quote Link to comment Share on other sites More sharing options...
Aaronz28 Posted March 5, 2016 Author Share Posted March 5, 2016 What is your goal? I'm a pure stock, from the factory person, everyone is different. Bruce I enjoy pure stock - but more than that - i like using the best performing GM "era correct" parts - the ZL1/L88 cam is to crazy for a heavy car with AT - so i thought the LS6 grind would be more than steerable - and using the tri=power is just cool! Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 5, 2016 Share Posted March 5, 2016 that is going to be an interesting build! I think the oval port heads are going to help in a big way, I would consider advancing the cam 4-6 degrees to help the bottom end, as long as your valve to piston clearance is ok I agree with David about getting the manifolds ported and would urge you to use as large as you can exhaust pipe with the oval port heads, and a properly matched converter, I think you'll be fine with the 3.31 gears very cool! build you have going here! if you are interested in coming up to Pontiac for Dream Cruise, Vince (vinniepooh) puts on a mini-meet for Montes, we've had it 2 years in a row now Quote Link to comment Share on other sites More sharing options...
Aaronz28 Posted March 5, 2016 Author Share Posted March 5, 2016 yes - i'm in for the Woodward cruise - also gonna bring the family to Norwalk this year for the meet. i also thing that the closed chamber oval ports - with the matching 3x2 intake, and the LS6 cam will be a killer combo. I extrude honed my SBC manifolds for the my 69Z - and didn't notice any difference for regular driving - the car currently has 2.5" dual system which is what i'll keep on it for now - should be fun. worst case scenario - the 3.31s come out and 3.73s go in Quote Link to comment Share on other sites More sharing options...
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