Heff Posted January 3, 2013 Share Posted January 3, 2013 Long story... but here goes I rebuilt my 402 2 years ago and have never been happy with it. bored .030 over, mains line bored & honed, .010/.010 on the crank reconditioned rods, ARP rod main and head bolts, complete assy balanced with a set of custom forged pistons from Diamond 41cc dome, slightly worked over heads (820's) original intake, rebuilt quadrajet and a Summit 1302 cam 228/238 @.05 286/296 advertised .540 lift on 114 LSA. my original intent was to keep it looking stock but have more power. Rebuilt TH400 with 10" converter stalls around 2800-3000, and a 3.55 posi 12 bolt. a year and a half later the motor is being pulled due to rings not seating correctly (I think? burning oil) anyways This combo never ran like I thought it would, seems like a real slug on the bottom end, could never get the dam Q-jet to idle or pull real hard, just doesn't seem like Big Block power under the hood. so... here's the question pull that motor, put it on a stand and start over with a 496 build, or new AFR heads, Eddy air gap intake, new Quick-fuel carb and a HR custom cam from Chris Straub? It’s about half the cost to basically do the top end kit for my 402 from Chris than it would be to do a complete 496 with the same top end kit, and I think that if I ever got the more cubes bug down the road I could use the same parts on a new 496 short block? This is a street driven car but I want more out of it of course, and I was surprised at the numbers Chris said I could get out of this little 408 in a VERY streetable package and way more than it has now. I know you guys have a lot more experience with engine combos and builds than I do so any thoughts or advice would be appreciated. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted January 3, 2013 Share Posted January 3, 2013 if is that much of a slug, I would check the cam timing, upon tear down, First I would do a compression test before you pull it second, if you are going to dump that kind of money, even a 454 over a 402 is a big difference, so I would jump to at least a 454, or pull out all the stops and do the 496 Quote Link to comment Share on other sites More sharing options...
Heff Posted January 3, 2013 Author Share Posted January 3, 2013 If I do a different engine I would do a 496 you may be right on the cam timming it pulls pretty good up top just no bottom? maybe needed advanced? I'll know more once it's tore down. Question, what would you consider to be good HP/TQ numbers for a fun street car that weighs 2 ton. trying to get an idea on what I should be shooting for? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted January 3, 2013 Share Posted January 3, 2013 IMO 500hp, that's where I'm at with a 9.5:1 454 and stock heads and pleased with it. I used to have much more with my old engine (well over 600hp) and the race fuel made it cost too much to drive Quote Link to comment Share on other sites More sharing options...
LS5 Posted January 3, 2013 Share Posted January 3, 2013 Hey Chad, on the burning oil are you sure its the rings and not the valve guides or rubber seats that are shot in the heads ?? did you have them rebuilt or had new valves put in and not change the guides ? As Sam mentioned the 454 is pretty good keeping with the stock appearance but has get up and go... in my 70 chevelle I had the LS5 rebuilt with the heads done and new valves etc and the block decked and bored out and the crank turned 10/10 with Keith black pistons and a Thumper cam and had it all balanced with stock low rise 454 intake and factory rebuilt carb and exhause and was sitting at around 440hp and man was I pleased with the rebuild on that 454.... but then again so was my local tire shop as well.....hahahaha.... for that stock look as you say and get up and go that 454 decaled up as a hidden 402 should be pleaseing and also as sam said I had to mess around with timing too....... just my 2 cents... Darren Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted January 3, 2013 Share Posted January 3, 2013 Chris is very knowledgeable, he did my cam. I have no doubt that he can make that 402 run. That being said, there is no substitute for cubic inches. I would do a 496 and use your current heads with a cam from Chris. 100 ft lbs of torque is very noticeable! Later if you are still looking for more you can bolt on heads. Your current oil consumption could be related to your Qjet tune. Quote Link to comment Share on other sites More sharing options...
Heff Posted January 3, 2013 Author Share Posted January 3, 2013 Mike that is an option as well, I could probably build a 496 short block for about the same price as the AFR's and complete roller package? I don't know how far my heads would let me go but I could keep that stock look and still produce a bunch more torque. Tell me more about the Qjet tune and oil consumption? Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted January 4, 2013 Share Posted January 4, 2013 Chad, If your carb is not right you could be gas washing the cylinder walls. Hard on ring seal and oil consumption. I did a similar 402 build for a member here. He has a little more cam with a 107 LSA and less stall on the converter and the Qjet works fine. Quote Link to comment Share on other sites More sharing options...
overdrive Posted January 4, 2013 Share Posted January 4, 2013 Are you running a PCV valves and aftermarket valve covers? Poorly designed valve covers can allow oil to be pulled past the PCV and into the carb. Like was posted earlier, do a compression check to check the ring seal. There's no need to pull it apart if the compression check is good. Dan Quote Link to comment Share on other sites More sharing options...
Heff Posted January 5, 2013 Author Share Posted January 5, 2013 The heads were shaved .005 just to square them up Original valves just touched up as well as the seats, new viton valve seals Factory valve covers, tried two different PVC valves both new The car would never idle right and always seemed like it had a vacuum leak. Checked all the lines multiple times, even replaced the intake gasket thinking maybe leaking there, and also possibly causing my oil consumption but didn't help. It's a moot point now because I pulled the motor earlier today, and pulled the trigger on the new AFR 265's Straub custom hyd roller Eddy performer rpm intake and quick fuel 850carb. I'm finally getting excited about this car again, it was just so frustrating the last couple years, it got to the point that every time I took it out for a cruise it would just make me mad and I just didn't drive It much. Hopefully I'll be cruising it this summer with a big smile on face again. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted January 5, 2013 Share Posted January 5, 2013 Good luck, I have heard good things about the AFR 265s. Chris did my cam, Bullet grinds them for him. Do they offer the CNC chamber option on the 265s? I opted for that on my 325s, great bang for the buck. Quote Link to comment Share on other sites More sharing options...
gprimm Posted January 5, 2013 Share Posted January 5, 2013 Heff, know the feeling on frustrated. Spent last winter getting my small block Monte right; just how I had dreamed of doing it for 10 years. Now, I love it. Nothing more I want to do. It'll be great when it is done and dialed in. I now love seeing a Mustang around Quote Link to comment Share on other sites More sharing options...
Heff Posted January 5, 2013 Author Share Posted January 5, 2013 Mike, they do offer it but I went with the as cast version. Chris did not think it would be worth the extra coin in my case due to the small displacement and stroke of the 402. I was a little concerned about the 109 cc chamber upping my compression too much but it should be ok with the aluminum heads. Based on your sig picture this is probably a dumb question but were you happy with the cam from Chris? Mine will obviously be different than yours, just wanted to here some first hand feedback. Quote Link to comment Share on other sites More sharing options...
Heff Posted January 5, 2013 Author Share Posted January 5, 2013 Now all I have to do is convince my wife that "AFR 265" is a car guy code for Almost Free Refurbished $265.00, besides new kitchen countertops are way overrated and do not add any HP Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted January 5, 2013 Share Posted January 5, 2013 I am real happy with mine, it is a solid roller. Chris did Crazy Davey's Hydraulic roller and he is deep into the nines. Are you pulling your 402 apart? If so check with Chris about relieving the top of the cylinder block at the intake valve. It helps with flow and big valves are close in the small bore. GM used to do it on the Hi Performance 396s. Quote Link to comment Share on other sites More sharing options...
Heff Posted January 5, 2013 Author Share Posted January 5, 2013 The 265's have the smaller 2.190 intake valves, but I will ask him next time we talk. I will be taking it apart, so now would be the time. Thanks for the heads up. Quote Link to comment Share on other sites More sharing options...
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