This subject has probably been beaten to death, but its my turn to ask. I am doing ground up on stock 77 L48 / Manual Transmission. What to do with the engine is in question.

I want to improve the torque as much as possible, but stick with the stocker air cleaner, quadrajet and the rams horn exhaust. I want it to look stock, but to do as much as I can to improve the torque. I do not abuse my cars or motorcycles, and will not be ever reaching 5000 RPM. That is why I really don't care about HP numbers, as they are always about high RPM, I am interested in increased torque in low - mid range. But I still like accelerating through the gears, just won't run it out. I figure with good torque, you get there without the abuse.

I would consider aluminum heads and intake, even though they are not exactly stock looking. The Edelbrock Performer packages seem like they may be what I want, but wondering if others like SR Torquers, etc may work. Definitely do not want Vortec, unless I can hide those valve covers with perimeter style.

One more factor, I probably switch to later model block with 1 piece rear, hydraulic rollers. Again, it looks stock, but is improved.

I might even consider a 383 for the torque, but worried about the limitations of Quadrajet and Rams horn. WIll I be wasting the 383 with these limits??

Appreciate any input.

 

A well tuned qjet will easily feed a 383. I think the rams horns will be a restriction for you with a 383, but others with more knowledge will probably weigh in here.

A stock motor with free flowing exhaust (i.e. no cat converter) and a more aggressive distributor and timing curve will produce noticeably better "seat of the pants" feel. New headers/exhaust more so, but you would lose some of the "stock look".

 

I was the same way with my 73. Wanted stock appearance but better performance. Heres what I did

Ohio crank rotating assy (383)
2.5 in rams horns
extrude hone intake and exhaust manifolds
Port and polish stock heads.
Mild cam shaft
Edelbrock carb
about 5000 in parts and another 5000 in machine coating and labor

Looks completly stock on the outside, runs very nicely, gets about the same gas milage. About 400hp 440tq. I am very happy.

 

I would consider an RV cam for low end torque if you don't intend on going over 5K.

 

Just some observations:
With your self-imposed rpm limitations, a 383 would be worth it for the torque advantage. A Quadrajet will work fine. Stock exhaust won't hurt as much at low rpms, as it would at high rpms, so stick with it. But, you said going thru the gears and limiting the rpms gets you there without the abuse - thats not true. You will significantly reduce your rate of acceleration by not winding the engine out.

 

Thanks for the replies so far and I am trying to understand some of the comments. Since the tach on my car is redlined at around 5300 RPM, it does not really seem as if I am limiting myself. Exceeding the recommended RPM is for drag racers and those who have more money than I to rebuild engines regularly.

And even with my 190 HP, anemic 77 L48, if I were to run out every gear to 5000 RPM, I would easily be doing 60-70 MPH before I ever got to fourth gear. So since I never top the speed limit by more than 10 mph, I see no reason to take it up to 5000.

What I want is to be able to accelerate quickly to max speed WITHOUT taking it to 5000 RPM. Its the same reason I choose Harleys over Ninjas when it comes to motorcycles. All that high RPM capacity on *** bikes is just a bunch of unnecessary noise for me. I prefer the low end torque you get out of even stock Harleys, and big block cars.

But since I don't have a 427 or 454 for the Vette, I just want to build a small block that gets as close as possible. A 383 seems like it would be good, but I really am wondering if I am wasting money on a 383 if I am limiting myself to a Quadrajet with maybe 2.5 inch rams horns i.e. stock appearance.

I read books on high performance mods, I find myself pursuing bigger and bigger ideas, then I realize I really don't want a race car, and for me, once you start modifying the car too much, you loose the character of what it is. Next thing you know you are putting on Bilsteins, composite spring, rack and pinion steering, etc etc. Don't want to go there. I once restored a 73 Harley Shovelhead, put big motor in it, all the best components, spent lots of money. It was a modern Shovelhead. I would then go to a bike show and see a bone stock 73 and wish I could trade!! I don't want to do this with the Vette.

I expect I will be getting replies that I might as well buy a Buick, but I hope there is some of you that appreciates where I a coming from and understand my question.

 

The tach reads just over 5000, so I don't understand why it seems limiting that I keep it under 5000. Unless you just don't mind abusing the engine.

 

Thanks for the input. I guess I need to qualify the winding out. I drove the car a year and a half before I tore it apart. If I wanted to get on it, I might get up to 3500-4000 in each gear, but I just don't like getting near redlines. With that type of shifting, I was never really impressed with the acceleration. I would imagine if I would have wound it to 5000 each time, it would have felt more like I thought a Corvette would. But I just feel like the idea of power / torque is that you don't need to take it to the limit each time. Same thing with my mildly modified 04 Road King. I have it cam'd for low end torque, and it is as much fun as I need getting to 60 mph. I am looking for the same thing in the Vette. I want to do something to make that 3500-4000 RPM accelerate the car faster, and still look like a stock engine.

 

Thanks for the input. I guess I need to qualify the winding out. I drove the car a year and a half before I tore it apart. If I wanted to get on it, I might get up to 3500-4000 in each gear, but I just don't like getting near redlines. With that type of shifting, I was never really impressed with the acceleration. I would imagine if I would have wound it to 5000 each time, it would have felt more like I thought a Corvette would. But I just feel like the idea of power / torque is that you don't need to take it to the limit each time. Same thing with my mildly modified 04 Road King. I have it cam'd for low end torque, and it is as much fun as I need getting to 60 mph. I am looking for the same thing in the Vette. I want to do something to make that 3500-4000 RPM accelerate the car faster, and still look like a stock engine.

 

I'd look for a 400" block or at least build a 396" smallblock. Use some better heads made of aluminum...Dart 200''s or similar will work fine. You can easily disguise them with some paint and a little fine sand mixed into the paint and a little grinding to round off the sharp corners. You're going to be working the engine hard under a load with lower revs so use heads with good combustion chambers to control detonation. Even though you aren't revving high..don't think tiny heads are the answer with 383-400 cubes. The Performer intakes will do well.

The stock 2.5" iron manifolds will choke it some..but with a 5000 RPM limit it will be OK if you spend some time porting them. Open them up and they do pretty fair. The Q-jet will feed it easily..so don't worry about it.

This 400" engine is a Dart SHP package with 200 cc heads. We worked to disguise it as the original 283/270 2x4 motor that is sitting on the engine stand in storage. We ported the original intake and reused the little WCFB carbs. It made 495HP with the WCFB's, 520 HP with a Dart dual plane and a Holley 750..and 555HP with a Weiand Team G and the 750 Holley. Even ported within an inch of its life..the intake was the restriction..not the carbs.

It also made 520 lb ft of TQ...so no slouch!

He drives it everwhere with a TKO 5 speed and 3.36's.

JIM

 

I often shift like the OP around town in my 61. Short shifting because of the speed limit. 61 weighs 3000 and has a 4.11. 28" tire . 355 AFR 190 heads, 224/224/110 fully divided dual plane w/4 holer.
Has no need for more torque! But when i used an open carb base gasket years ago, torque was way down below 2400. I can see why guys stroke it to get more torque. But, i found an easy way to get back that torque! So my point is, small details make a big difference. see link in profile sig.

 

If you are changing the motor up, then whatever redline your stock tach reads is more or less pointless. Thats redline for your bone stock L48, but may be no where near redline for a well built 383. Im working a 383 build right now that will have redline closer to about 6200. 5000 should be a walk in the park for it. I would focus less on what the tach says and just build the motor according to your desires. Pretty much anything you do is going to be a vast improvement over the stock L48. You dont sound like you drive really hard, so I wouldnt spend the money on a 383 build, or even a 400 block. Just go through your block, maybe new pistons, a good low end torque cam and new heads. That should get you where you want to be without spending 5k or more!

 

I have always wanted to do the sleeper thing. I was going to do it but these days no one will put down any money like back in the 70-80's on the back road drag strips. ( Please no holier than thou replied because if you own a Vette you've street raced at one time or another, taking off from the lights to show that Honda beside a thing or two, that's stunt driving, nowadays I don't street race period)

There is one 400 block that has the same amount of freeze plugs as the ordinary 350. Would love to put a 4 inch crank it it, a bigger hydraulic cam and up the compression. Then get an old set of ported iron heads that look like the 882's and use the factory rams horns and exhaust.

Yep stock 350ci, willing to race ya but only for 50 bucks as your Mustang looks pretty souped up

As far a the original poster goes, if you want to keep it stock looking, just throw in a 3.75" crank and a bit bigger cam, up the compression ratio a bit and you'll have a nice stump puller

 

Reminds me of the tech at the dragstrip I go to. Never lifted the hood just said "stock" and I said "pretty much" as all '80's come with 427 numbers on the hood, then went out and ran 121mph

 

For your outlined goals, springing for a lot of high dollar parts is probably a BIG waste of $. Especially a roller cam, aluminum heads, etc. unless you find great deals on used parts somewhere.

I think your best bet is an appropriately cammed, simple, old-school 383. Throw on a decent aftermarket low-rise aluminum intake that will fit under your stock hood and accept your Q-Jet & air cleaner with no issues. Also, you'll be able to use all your stock accessories, etc. except for the harmonic balancer and flywheel.

You could buy a cheap stroker kit and re-use your block & heads (my choice) or go quick and easy with a new long block something like this:

http://www.summitracing.com/parts/ML...2CT1/?rtype=10

I've used one of these intakes under my 72's stock hood in the past on a similar engine with the Q-Jet and it ran great on the street and made low 14s / high 13s at the track (shifted above 4500 tho ):

http://www.ebay.com/itm/WEIAND-SBC-2...665#vi-content

I think this particular Weiand model may be OoP, so look for a good deal on a nice used one as above. If you want an aluminum manifold that looks stock (because it is...), go L-82:

http://www.ebay.com/itm/Corvette-L48...a46a42&vxp=mtr

Get your stock carb rebuilt by one of these guys:

http://www.cliffshighperformance.com/
http://www.everyday-performance.com/

...and it will make more power and get better mileage than any new carb you might buy.


Rams horns should be totally adequate for 4500rpm and under. Have them acid dipped (and ceramic coated cast iron grey if you want) and put a decent mandrel-bent 2.5" exhaust with Dynomax Ultraflos behind them.

With traction in your stick-shifted car, if you tried hard enough, the above combo should be enough to eventually break your stock u-joints, half-shafts, and/or diff if they haven't been serviced/upgraded recently... (hint, hint)

Just my $0.02.

Good Luck & Have Fun!

P.S. I completely endorse your purchase of a Buick as long as it is something along these lines:

http://www.youtube.com/watch?v=qB7VL...ure=plpp_video

BTW... she's running the as-built-by-GM low compression 455 engine with a Q-Jet and iron manifolds (and about 500+ lbs more than your Vette).

 

the comp 268 extreme hyd cam will make good low end torque with your current 350.I like the 383 short block route with some dart iron heads. some one else on here had a 383 delivered to their door for under $2500 I believe.your quadjet can be rebuilt and handle the power level you want.check competition products for a 383 stroker rotating assembly,they start at $600 to $950.

 

If you have enough head flow to take advantage of the extra lift,
you might want to think about some 1.6 roller rockers.
The quiet is always nice and cooler too!

R

 

How is my 77 L48 two bolt main, two piece rear seal going to hold up with 383 torque? That is my concern. I have not even disassembled the engine yet, and who knows what I will find. I really can't see using my stock L-48 heads with a 383, that really seems like a bad direction.??

Skip White has a one piece rear seal, four bolt main block clearanced for 383 and I thought about that as starting point. I like the Scat cranks, seem to be high quality. But then, I don't know where to go from there. THey offer the Probe pistons, but compression is too high for me.

I still am thinking Edelbrock Performer RPM heads and intake, maybe with Comp Cams 262 or 268 Extreme Energy.

??

 

i found a good build, i posted it earlier as "warmed over 350" they did 365hp out of a 355 which is more than enough IMO, i just ran an 8.62@74 in the 1/8 in my "stock" L48 last night. these cars dont need much, just lighten them up.

 

If you're going to shut it off at 4500 rpm, I don't see how you need any more cylinder head than what you have. Will you be able to move more air than that at such low rpm? I would be concerned that if you went with an intake & heads designed to make power past 6000rpm, low engine speed power & torque would actually be LESS than the same 383 under your worked L-48 heads at 4500. L-48 heads were intended to run under 5000, RPMs were not (unless they are on something like a 450 cubic inch smallblock). The best argument against your stock heads in your proposed combo is that iron sbc heads are so cheap that you probably can buy new ones for equal or less cost than to rebuild your old ones. Same deal for two bolt mains, at 4500 I would think they would be fine unless you're throwing a bunch of boost or nitrous at it. Two piece rear seals lived behind every hi-po factory small block for the first 30 years of SBCs...