flyguy767

Have a 350 SB 1977 L48. I want to pull the 89K mile good running engine out and replace with a built 350 SB around 350-400 HP. I don't want to totally break the bank over it, looking for suggestion; aluminum heads, cam maybe etc. The plan is to build the replacement engine and still have use of the car until it's ready be installed. Maybe I should even consider a different engine altogether that will match up with my Turbo 350 tranny, or maybe I should change that to a four speed? Want to make the best bang for the buck and achieve my goal of 350-400 horse and have a street legal vehicle.

c3_dk

I would start to look here, if I was you, that you give you an idea regarding price.

http://www.cnc-motorsports.com/

Also, I would, if I was you replace the TH350, with a TH2004R and 3.70 or 4.11 rear, then you would be flying :-)

Bloodzone

Be ready to spend some cash. Things do add up. Let me give you my list. Swapped L48 for 383. Added LT headers and dual exhaust. Changed to 700r4 trans with 2800 stall to match 383 cam. New mini starter with heat shield because header heat killed old starter. Dewitts radiator & electric fans to cool 383 better. Carb spacers, fuel line insulation, external transmission cooler. I'm not saying your gonna need all this but it may cost more than you think.

flyguy767

I have a 350 small block that's been bored to .040 over and going to start from there. My son in law is a master mechanic, so with his help and around 3500 bucks I was hoping I could put some power in my 1977 L48. He suggested aluminum heads with larger intake and exhaust valves. Maybe a new cam also to start.

bluedawg

Scat stroker kit.
Good aluminum heads, afr, dart ect.
Well matched roller cam dependant on head selection.
Edelbrock rpm air gap.
Long tube headers.
Dual exhaust.
Stall converter matched to cam.
Cost 6k or so.
Fun priceless.

toobroketoretire

If you want a LOT of torque at a nice low rpm swap in a 454".

96 lt-4

Everyone and their brother has advice on how to build a small block chevy.

Compression
head flow (the power is here 180-195cc aluminum for best results)
properly matched cam/intake/carb to work with your torque converter and rear end gears
Don't skimp on parts(good double roller timing chain and no chinese roller rockers)
Recurve your distributor.
Tune it.

Everyone will tell you to do a hyd roller cam,overdrive trans,and lower rear gears.That is great if you have the cash.Trans and gears can be done later if desired.You don't need a hyd roller to make 400hp but there are advantages for power and longevity.

For that matter you could likely do a heads/cam/rockers/intake to your short block and achieve your goal.

REELAV8R

My 77 has the stock block in it, not bored over with roller cam and Dart SHP heads. Makes 400 ish HP as of a week ago.

I would not recommend the Dart SHP heads assembled. Not assembled they may be a decent option. Now though the price is $1000 unassembled so given that for a little bit more I think you get a much better head in the AFR's.
Roller cam conversion I can strongly recommend. Mine is a Lunati retro roller 270/270 advertised 219/219 @.050, .549 lift with a 108 LSA. Pulls real strong from 3000 on up. At sea level would probably pull starting at 2300 or so.

The engine can only perform as well as the exhaust and intake system. So a good 2 1/2 inch out the back with 1 3/4" primaries would work or side pipes for a mostly un-restriced exhaust which is what I run.
Intake I use is the Edelbrock Performer 2101. Would like to have a better intake, but hood clearance is an issue with these cars, and I'm running the stock air cleaner set up slightly modified.

Your 3.08 rear diff is a bit of handicap. You will need a stall converter for better launches from a stand still with any decent duration.
I'm using a 2600 currently. Works pretty good.
The TH350 is a nice cheap and reliable transmission. I replaced mine with a B&M 500 HP rated unit with a shift kit $800 delivered. Stock unit needed a rebuild. Shift kit makes the shift nice and quick and firm while at WOT. Big difference vs the stock trans.

400 HP is pretty fun, and it won't break the bank so it's a good goal.

flyguy767

It's gonna be a weekend around town car, maybe 4 or 5 he trip to the beach once in a summer. I just want more get up a go. 180 hp is pretty weak for a car like this. I know my 350 tranny can handle up to 359 or 400 hp my diff. I think is 3:55. Definitely gonna go with aluminum heads, 2.02/160 and 64cc bore and a cam. Something will work with tranny back for now.still gotta do some interior work. I am not going to race or go to drag strip with it. Just want the power if I need it and the cam should give me that nice rumble in the motor.

ykf7b0

I too had an unimpressive 180 hp 76 L48. I have just recently swapped to factory vortec iron heads, aluminum intake manifold, hooker super comp ceramic coated headers, and free flowing 2 1/2 exhaust. These changes have somewhat woke this engine up. I wasn't up to a much neeeded cam swap but it is in the future.

mbhnm

I concur with most of the advice you have gotten here. Number one issue with a 77 is the pitiful smog heads they came with. Simply swapping the heads with a good aluminum 2.02/1.60 valve setup would be the highest bang for the buck. I would keep these in the 180cc intake range if you want good low end power.

Second I would recommend changing out the camshaft and timing chain. A roller cam for your engine is going to be expensive and is really not necessary so long as you keep the lift down. My 383 is running Comp Cams L79 with 0.46 lift and I still produced 440+ horsepower.

You can also get a boost by changing out your stock intake manifold for a nice dual plane unit with a decent carburetor. My dyno guy recommends 600-650cfm for a street 350. I used a Weiand Stealth on mine as it seemed to be the tallest that would fit under a stock hood. Headers will also give you a significant improvement over the cast iron manifolds.

If you are pushing 400 hp you want to make sure your bottom end will handle the stress. My machinist recommends 300hp max for a stock crank and two bolt mains.

If you want to get some ideas look at my post in this section titled "383 engine build for a 76." It has a list of all the parts and specs I used for my build and I am adding posts about the actual build process as I am able.

Bottom line is that it is going to cost some money to do what you want to do. But I guarantee it will add smiles per gallon!