masters

GOING TO REBUILD MOTOR. IF I KEEP BOTTOM END BUT CHANGE PISTONS,
CAM AND INTAKE, PORT HEADS ETC. WHAT PARTS SHOULD I USE?WHAT OUTPUT WOULD I GET IE: HP AND TORQUE? MOTOR IS L48,4 SPEED WITH 3:36 GEARS. WHAT PARTS DO YOU SUGGEST I USE? IF I DO THE ABOVE BUT CHANGE HEADS AS WELL AND RUN HEADERS WHAT ITEMS DO YOU SUGGEST I USE AND WHAT OUTPUT WOULD I ACHIEVE. WANT TO GET OVER 300HP. THANKS FOR ANY REPLYS.

7t5

I would imagine just a cam, good heads and a free flowing exhaust and an intake would get you pretty close to 300 hp. Definitely change the heads. By the way, I think pistons are considered to be "bottom end" parts. If the motor is in otherwise good condition you may not need to change any of the bottom end as it is more than strong enough to support that kind of power.

comp

:iagree: if shortblock is still in good shape a cam change (mild/med) street
performance grind, a set of head's (mild) will be a nice upgrade, Don't forget
headers and duel exhaust 1st on the list :thumbs:

vettfixr

When I rebuilt my L48 at 90K miles I measured everything and it was all within acceptable tolerances so don't assume you will have to replace a lot of parts until you check it all out. I had no machine work done to the block at all. I went with the original crank rods and pistons which I cleaned up before reinstalling. I bought my engine kit from Summit which included new rod and crank bearings (Clevite 77) and new moly rings along with a high volume/high pressure oil pump and a gasket set. I replaced the heads with World Products SR Torquers with 2.02 x 1.60 stainless valves and 67 cc chambers to bump up the compression a little. I replaced the cam and bearings using a Crane HMV272 dual pattern grind which is now referred to as a Powermax 272 cam. It has 216 and 228 duration @ .50 for intake and exhaust and lift is .454 inches on the intake and .480 on the exhaust. It idles at 800 with a nice lope and gives me 14 to 15 inches of vacuum and has a nice bottom end to complement the upper range. I used a Performer knockoff intake and an Edelbrock Thunder Series 650 cfm carb. As you can see in my sig a Desktop Dyno run shows approx 338 horsepower @ 5000 rpm and 394 torque at 3800. It's a nice strong reliable engine that I hope will give me many more miles. It uses zero oil and has no tempermental problems. In total I probably have less than $1K invested in it. It's not going to set any track records but for a turn the key and go solution you can't do much better.

comp

sounds like a nice combo to me, cam sounds like a real good one for many
mild builds :thumbs:

masters

WHAT EXHAUST DO YOU HAVE? I'VE BEEN CONSIDERING THE TORQUER HEADS AS WELL.

vettfixr

I have Dynomax Ceramacoat headers going into a 2 1/2 inch stainless system with a crossover just before the tranny. Out back I have a set of polished Dynomax Ultraflows. When I first installed the ultraflows I thought they were very quiet, in fact they sounded a lot like the stock mufflers until you put your foot in it. Now that they've been on for about a year they've broken in and sound just nasty enough to get attention but not to much to be annoying. There is very little resonance in the cabin and it only occurs at about 1200 to 1500 rpm. Here's a few pics. The last pic shows the Ultraflows. The pic next from the last are the older stock mufflers. Notice that the Ultraflows, as sold by Mid America, have shorter pipes that connect to the main system so you end up using the offset toward the center of the car which puts the tips toward the outside corners. No biggie but you have to play with the rear hangers to get them right.








[Modified by vettfixr, 7:17 PM 5/6/2004]

redwingvette

Crank should be ground with new barrings, flat top pistons, rings, heads, cam/barrings, lifters, intake, oil pump, and exhuast