Buy a late TPI engine and swap a carb intake on it and a Lingenfelter 211/219 roller cam and call it a day, even the oil pan fits a C3 chassis. Gets you good compression, a 4 bolt block, aluminum heads, roller cam and you should be able to find one from a wrecked Vette pretty cheap. Later, you could have Lingenfelter CNC port the heads, put in the 219/219 cam, 1.6 roller rockers and make 400+ HP. If you REALLY want to have fun find a running 400 cube small block, swap some decent heads on it, one of Lingenfelter's flat tappet TPI cams, and put 2.73 gears in the rear, with all the torque of the 400 you won't give up much acceleration potential and highway driving will be sweet !

 

The TPI engine I had in my camaro was full of torque but it ran out of steam about 4500-5k and only made about 250hp... Thats a lot of work wiring in a computer and or sensors and such for 30-40 hp.... I know there are tpi engines in newer corvettes that made more power but if one was to go through all that trouble then a ls1 or newer engine is the way to go... all of this is way overkill for folks like the OP who just want to wake the car up a bit and not change it into a different car.

 

I said put a carb intake on it, that means lose the TPI, he could sell the TPI stuff to recover some of the costs, no wiring changes at all, and the cam change and carb setup will unlock quite a bit of power... Plus the car isn't a paper weight while the engine is being done. And he most likely has a 2.88 first gear in that BW Super T-10, so pulling a 2.73 gear in first and second won't be a problem. It's basically a ZZ4 350 with a better cam, 1.6 roller rockers, intake, and headers with dual exhaust.

 

But the whole reason the tpi engine had all that torque was from the long tuned runner design of the TPI intake manifold? it was my understanding the TPI heads arent that great... the best version were the fast burn zz4 heads used at the end but even those dont flow as well as a set of $600 aftermarket or vortec heads? I just dont see the benefit over just picking something like this up "while the engine is being done"

http://buffalo.craigslist.org/pts/4483606455.html

 

The ZZ4 with the Vette aluminum heads was rated at 350 HP, now we swap in a better cam with slightly more duration at .050 and more lift, increase lift further with 1.6 rockers, use the taller (better than ZZ4) air gap intake, headers and duals, and it will be more than 350. He could also disassemble the TPI engine CAREFULLY and have the heads ported and the block zero decked and put in the 219/219 cam (roller) and make 400+ HP all day long, with a lighter engine to boot (aluminum heads and intake, and have to change water pump to V belt style pump so might as well put on an aluminum pump too). I would try to find some TRI Y headers also to increase torque even more.

 

There's also a side benefit to this approach as well, let's say the OP upgrades his numbers matching L48 engine, and something happens...drops a valve, over rev's it, whatever, and he hurts the block...bad enough that he needs a replacement...unlikely, but possible. Now his numbers matching car...isn't. Will it affect value ? Maybe...

 

My cousin has a 1973 L48 4 spd Corvette with 3.36 gears. We found an old early 70's Impala with a 400 in it for 1000 bucks. We removed the engine and sold the car for 600 bucks. We took the crappy 1.94 1.50 heads off, found some 487 (71-72 LT-1 heads) with 76cc chambers, bowl ported the heads and back cut the valves and had new guides and a valve job done, milled the heads to 72cc, steel shim gaskets, put Lingenfelter's biggest flat tappet TPI cam in it, ported his stock L48 intake, 800 cfm Q jet from a Buick 455 (junkyard)1.6 roller rockers, Brezinski's ported early Vette 2.5" exhaust manifolds on it, and a Pypes 2.5" X pipe exhaust. We swapped 2.73 gears (found a center section on Craig's List), and converted his Muncie to wide ratio...that car is an ANIMAL ! And it's quiet and smooth as can be. And it looks stock on the outside. Gets decent mileage too. The potential of hurting his numbers matching engine was the push over the top to swap engines, plus he could keep driving his car while the engine was being built (this all didn't happen overnight, obviously), and the gear swap (rear and trans) made the car a lot nicer to drive on the freeway. The car has tons of torque for around town or passing on the highway. It's NOT drag raced and never will be, but it keeps up with plenty of newer high tech hot cars on the road and it's fun to drive and never over heats and has been reliable for 10+ years like this.

IF we ever decide to do anything else, we'd find another 400 engine and have it machined .030 or .040 over, zero decked, 3.875 stroke crank, 5.85 rods, same cam and rockers, better cast iron (aftermarket) heads with mucho porting done and maybe a later aluminum L-82 intake with porting and an aluminum water pump and make more power and torque...and still look and sound stock. ;-)

I tried to get him to put 3.55 gears in it with a 5 (or 6) speed trans, but he wanted the stock look and feel of the Muncie, and he drives the car to work in the summer sometimes on nice sunny days (50 miles each way roughly), so 2.73s and a wide ratio gear set in his stock close ratio case was as good as we could do for balancing acceleration/power with fuel economy and lowering cruise rpms...The 400 makes so much torque down low I don't think it's really a big deal.

 

Thanks for all the info guys, I called a machine shop near me and asked them about milling the heads from 64cc to 58cc and they could so it for $100 so I ended up ordering the profiler heads and I'm going to mill them to 58cc, I know their are other heads for cheaper but I like all the reviews I've seen people right about them, so far I haven't read anything bad quality wise, except how long it takes for them to ship when they are out of stock, which I'm fine if I have to wait a little while, it'll give me some time to get all the other parts. Also I ordered the voodoo 262/268 cam I feel like I'll have a solid setup that I don't have to worry about for awhile lol

Also I would have considered the engine swap but I don't have any place to store my original engine, I'm okay with taking to chance of something going wrong, I plan on keep this thing forever and passing it down to my kids when I have them

 

This is a fairly shortsighted view of things. By the time you pass it on to your ungrateful, spoiled brat kids, that's just about when having a numbers matching engine will have a substantial effect on it's value. Besides, there's an old Jewish proverb: You want to hear God laugh? Tell him your plans!

Scott

 

If I didn't have an oil consumption problem (going to swap intake gaskets this weekend to see if that helps... intake may be sucking oil from lifter galley), I would have 100% positive things to say about an L48 buildup. As it is, I have 99.9% of good things to say

I've been boosting performance of the 2-bolt main L48 engine in my C3 since purchase in 1997. I started with the simple stuff:

• K&N filter
• rebuild/reinstall the cold-air induction
• Dynomax Super Turbo Mufflers

then, I rebuilt and added:

• Speed Pro H345NP hyper pistons with .020" overbore
• Crane energizer cam (272-H10 grind).
• Rebuilt '882' casting heads (replaced my anemic '624' castings)
• headers
• true 2.5" duals to my Super Turbos
• high volume oil pump
• other parts that came with the Northern Auto Parts 350 Performance rebuild kit
• Hedman Hedders (68301's)
• Accel Performance replacement HEI distributor
• Edelbrock Performer intake (3701)
• 1.5 ratio Summit stamped steel rocker arms

With this, I was rewarded with 190rwhp... not great but better than the 160rwhp that I started with.

I then added:
700R4
DART Iron Eagle heads (see sig for specs)
Lars-rebuilt qjet
performance distributor recurve
3.54 Spicer gears and blueprint of a new Dana 44 diff

and was rewarded with 224rwhp and 289rwtq.

That was the state of tune until winter 2012.

then, I added:
Comp Retro-roller K-Kit (see sig for specs)
stock volume oil pump (for the distributor gear to cam gear)
refreshed DART heads (sig) with the springs, keepers, locks and seals from the K-Kit
Comp 1.52 ratio Ultro Pro magnum rocker arms (probably the most accurate multiplication ratio rocker I've EVER had)

I have not had the vette on a dyno. But, it feels like it is finally getting all of the benefit of the flow capabilities of the DART heads with the .502/.509 retro-roller cam from the 1.52 ratio Comp Ultra Pro Magnum rocker arms. I HOPE it is getting north of 280rwhp and a good torque bump. The car accelerated and pulled like crazy with the Crane cam. Now, it really feels ALIVE at all acceleration points and smokes the tires from a standing start and through first gear.

It has been a BLAST to see what I could do with this L48. I probably will not replace it until I retire... and maybe not even then if I can revive it (if needed) to keep it running well.

By comparison, this engine (and the C3 in general) accelerates off the line and while driving better than my '69 L46 ever did with an M21 and 4.11 gears (just my opinion).

It has been a GREAT learning experience to have done most of the dis-assembly/assembly work, research on the 'forum and to have added to my tool collection in the process.

 

As far as oil consumption...do you have aftermarket valve covers on this engine ? If there is an un-baffled PCV valve in an aftermarket valve cover it WILL suck oil into the engine. Just something to look at if you have non factory valve covers.

 

If you have the heads surface milled that much, I would verify the fit of the heads-to-intake-to-block.

 

You make a good point but I still don't have a place to store the L48 so I'd rather just up the horsepower now, and when I have the room and the money I'd like to put an ls1 into it , but that's not for a few years so I want something to get me by for now that will still produce good hp