Rehabing a Malaise-Era SBC

Here's the deal. In order to park my soon-to-be Z06 in the garage, I need to get the 79 Corvette running. It's sat for about 8 years when the water pump went. Being 16, I had no money for such a project and parked the car. Now, I plan on giving it to my mother as weekend cruiser/Friday DD.

I've been slowly collecting parts over the past few years: I have new PS lines (need Pump) New Copper Rad and Rad hoses 70 LT-1 Finned Valve Covers GMPP Deep-Dump pan w/Windage Tray Aluminium H20 Pump New Bosch Alt Re-Built L-82 Quadrajet and L-82 Intake Manifold Stock HEI Distributor with new Delco Cap/Rotor/Module and Mr. Gasket Re-curve spring kit Every Chrome Mr. Gasket component Advance sold (store closed, 75% off)

I figured I can fire up the powder coater and rehab most of the remaining bracketry, etc. I have also started to re-wrap the wiring harness and am debating what to do with the (dead) AC.

Here's the thing, I don't know E36 M3 about SBCs, other than parts are cheap. I see used Carillo and such Rods on eBay for a pittance. I'd like to pick up a 4-bolt main block off of Craigslist, they can be had for next to nothing as well. A Eagle 383 Stroker Kit is around $800. Is there some kind of "Grassroots" Stroker Kit I could put together by mixing and matching OE parts? I see all these surplus cup parts all over the internet, could they be employed in the building of a strong bottom end?

A friend claims he can port the stock 1.94 heads and bring them up to "2.02" specs as an LT-1 would have. I've seen some on here mention Vortec heads. However, I'd like to keep the stock valve covers. I have no real idea what to do as far as valvetrain goes. As you can tell, I'm trying to keep things OEM on the outside, and not looking to spend big $$ on something that will never see a track.

Everything will be backed by the TH-350 for now, with shift kit added, new Torque converter, and possibly a trans cooler?

Any suggestions are appreciated. The car doesn't need to be anything special, I have no HP goal in mind. However, I'd like it to be at least able to get out of it's own way, and be reliable. I'm sure, when complete, my parents would like to use it for weekend trips and we'd be taking it to Carlisle. I'd like to add in a 700-R4 down the line, but that can wait.

The 383 stroker kits are a 400 crank and rods in a 350 block. They were junkyard before they came in a kit. The crank may need some machine work to fit, though?

Wheels777 (Screen name of a prominent member here) is your man for this kind of build, I think. Andy knows what cheap swap meet parts to combine into a challenge winner, from what I understand. And I know from first-hand experience, he's a darn nice guy.

I would definitely do a 383 kit vs. trying to piece it together myself. I believe Scat and most assuredly other companies sell cranks for this sort of thing that do not require block machining to fit.

A 350 or 383 with Vortec heads, a good intake (Edelbrock appears to sell a Performer Air Gap that accepts spread-bore carbs like your Q-Jet) and a decent cam will be a huge improvement on your 'vette. I don't know what the rev characteristics of a good 383 are really like, but for a Corvette, I wouldn't bother with one when there's already a 350 there to begin with. Honestly, I'd rather skip the added cost and instead find the parts required to do a TH200-4R swap in place of the TH350.

Block may need some machining for the 400 crank. (minor)

If it's just a cruiser, the 350 will have plenty of go without the extra dough for the stroker kit. 1.94 heads are better on the street, 2.02 will bog at low RPM.

Mazda787b wrote: Now, I plan on giving it to my mother as weekend cruiser/Friday DD.

Stock SBC not enough for Mom? Seems like a lot of trouble if it's only a weekender, sunny day Mom car.

Dan

MadScientistMatt wrote: The 383 stroker kits are a 400 crank and rods in a 350 block. They were junkyard before they came in a kit. The crank may need some machine work to fit, though?

no one builds them with the short 5.56" 400 rods any more- they either run the regular small block 5.7" rods or aftermarket 6" rods.

my advice: if you have all the parts you should keep it a 350 and don't worry about getting a 4 bolt block. the stock pistons should be flat tops, which means somewhere around 10:1 compression ratio with a set of stock vortec heads. top off the motor with the matching Edelbrock Performer Vortec intake with the stock quadrajet carb. put a mild cam in it- Crane 268H or equivalant- with a set of 1 5/8" long tube headers with 3" collectors and have a wonderful combination of plenty of low speed torques to keep you happy and about 400 horsepowers to pull you away from 95% of everything you will ever find yourself racing against..

novaderrik wrote:

MadScientistMatt wrote: The 383 stroker kits are a 400 crank and rods in a 350 block. They were junkyard before they came in a kit. The crank may need some machine work to fit, though?

no one builds them with the short 5.56" 400 rods any more- they either run the regular small block 5.7" rods or aftermarket 6" rods. my advice: if you have all the parts you should keep it a 350 and don't worry about getting a 4 bolt block. the stock pistons should be flat tops, which means somewhere around 10:1 compression ratio with a set of stock vortec heads. top off the motor with the matching Edelbrock Performer Vortec intake with the stock quadrajet carb. put a mild cam in it- Crane 268H or equivalant- with a set of 1 5/8" long tube headers with 3" collectors and have a wonderful combination of plenty of low speed torques to keep you happy and about 400 horsepowers to pull you away from 95% of everything you will ever find yourself racing against..

Agreed. 383s are neat, but IMHO, not worth the trouble unless you need the cubes for a performance goal.

Now, if you need to BUY a crank during a rebuild because your original is wasted, then its no more real cost to buy a 383 stroker crank. You will have more money invested in external parts (383s are external balance... you can have it internally balanced, but you're looking at a lot of Mallory and a lot of money, so you'll need a 400-style damper and flexplate/flywheel.

Skip the kit, build the 350, done. You'll want to choose pistons and head chambers that raise your abysmally low compression (what were they... 8.2:1 in 79?). I would also sell the heads to a restoration freak. They are terrible. Did I say terrible? I meant "not worth their weight in scrap."

If you're looking for more oomph, I might ditch the L82 intake. They're OK, but you can sell it to a collector and buy an Edelbrock Performer.

What are your HP goals? Use for the car? I can put a package together with my hands tied behind my back. Just let me know.

914Driver wrote: Stock SBC not enough for Mom? Seems like a lot of trouble if it's only a weekender, sunny day Mom car.

Well, she used to have a 6.6L 76 Trans Am back in the day.. I'm sure I'll be driving it on occasion, as well as my father. Let's just shoot for, say, ~350 rwhp.

Original bottom-end is most likely fine as far as re-using components. Was rebuilt at some point during the late 80s. I don't care about originality, or matching #s. I just had the L-82 intake (4 of them, actually) sitting around. The performers are less expensive than I had originally believed, so that's no big deal.

Crank could most likely be ground, as well as re-sized rods. I was thinking forged rods for more piece-of-mind but this isn't based upon any real-world experience.

I've seen center-to-perimeter bolt adapters, which would open the doors to Vortec heads, but I'm open to other opinions (be it aftermarket, whatever). As far as rockers/lifters, is stockish stuff good enough, or do these need some attention too? Don't get me wrong, I don't mind spending money on good stuff, but I'm trying to not open a can of worms here.

As stupid as it sounds, I have to use these valve covers. Mine are just polished, though.

As far a pistons go, would something like this be suitable to my type of application?

I should've also mentioned, I have a full mandrel-bent 2.5 dual exhaust w/H-pipe into Flowmaster 50-series mufflers. Also have tubular exhaust manifolds off of a cross-fire car which would need EGR tubes removed. I figured it would be easier here to sell these and pick up a generic set of shorty headers. I'm also in the process of investigating/drawing up a new vacuum diagram to rid of all emissions equipment.

Funny thing is, I have the suspension all sorted out for this thing, but I don't know jack about SBCs.

Mazda787b wrote: Well, she used to have a 6.6L 76 Trans Am back in the day.. I'm sure I'll be driving it on occasion, as well as my father. Let's just shoot for, say, ~350 rwhp.

350 at the wheels means about 425-450 at the crank. Considering that her 6.6L T/A made about 180 RWHP, she's in for quite a shock. :)

There is nothing wrong with 450 at the crank and don't let me talk you out of it, but you kinda cross a threshold when you go above 1 hp per ci. 350 cubes and 350 hp is pretty easy to do with cheap parts. 450 will definitely mean a big step up in investment. Just FYI.

Original bottom-end is most likely fine as far as re-using components. Was rebuilt at some point during the late 80s. I don't care about originality, or matching #s. I just had the L-82 intake (4 of them, actually) sitting around. The performers are less expensive than I had originally believed, so that's no big deal.

Nothing really wrong with the L82 intake, but it will restrict flow in the higher ranges. You'll need a dual plane, but step up to the Performer RPM. You'll need the extra flow. Don't fall for the "air gap" BS, that is a whole different soapbox that I won't get into now.

Crank could most likely be ground, as well as re-sized rods. I was thinking forged rods for more piece-of-mind but this isn't based upon any real-world experience.

Yeah, 90% of the time its just a regrind and go.

I've seen center-to-perimeter bolt adapters, which would open the doors to Vortec heads, but I'm open to other opinions (be it aftermarket, whatever). As far as rockers/lifters, is stockish stuff good enough, or do these need some attention too? Don't get me wrong, I don't mind spending money on good stuff, but I'm trying to not open a can of worms here.

$200 will get you some good rockers. Stockers will probably give up a lot of durability at the spring pressures you'll need to go with the cam. I tried making 350 hp with my Pontiac 389 on stock components and ended up with a couple bent rockers, a bent pushrod, and a rocker stud pulled out of the head. Chevy's are very similar in that aspect. We'll get into heads/cover bolts below.

As stupid as it sounds, I have to use these valve covers. Mine are just polished, though.

Not stupid at all. I have based entire build designs on one component before.

Recipe for 350 hp:

• Stock bottom end, all refreshed and rebuilt
• Heads: First, check what you have. They are probably a very poor choice for performance. Its possible they are #882 (last three of the casting - under the valve covers near the middle of the rocker studs). 882s aren't terrible, but that is something we'll get into later. They have large chambers which will require domed pistons. That isn't the end of the world, but I'll explain later why it has trade-offs. Choose a head that flows about 210 cfm on the intake at .500" lift. Whatever head you choose, go with 9:1 compression final assembly.
• Intake, Performer RPM (or similar)
• Carb: that Qjet is the finest carb ever created. I collect them because I friggin love them.
• Timing curve should be set to about 12 initial and 36 total with the curve "all in" by 3000.
• Cam will probably be something like 218/224 duration (look for something like Comp's XE262) Many times you can source performance cams from your machinist that don't require the big price tag of the big names. Melling, Blue Racer, Reinz, and other companies make cheaper cams. Also, trust your machinist on valve springs. DON'T trust Comp or Crane. They'll sell you the wrong thing. More on that later.

That should get you a good square 325-350 hp at the crank.

Great, thanks for the recipe so to speak. I've put a call into a roundy-round friend who has a spreadbore Performer RPM sitting around that the rules won't allow him to use any longer. Going to trade straight-up for one of the L-82 manifolds I powdercoated.

Heads are 487x castings. I heard some conflicting information regarding these from said friend when it comes to specs. However, I've been led to believe that they are better than what would've come on the L-48 in 79.

I would probably pass on help from someone that says they can change the size of the valves in the heads just by porting them lol. If I remember right the 487x heads are about the best you could hope for on a stock 70s 350, similar to the 882 but with larger exhaust ports and supposedly more resistant to cracking. If I was building one I would pretty much do just what curtis said, with these pistons (or whichever of the same type would give the right compression ratio with the heads I used), and probably this cam.

I dumbed the valve thing down a lot. He could port a 1.94 head to flow similarly (or better) than a 2.02 which I was originally looking for.

My machinist used to do engine work for Wayne Gapp, of Gapp and Roush. He now mainly does aircraft engines. Living in Detroit does have some perks.

Now that it's obvious that the heads aren't original, I think I'm going to have to have them cc'd and find out how big the combustion chambers are.

Just do a refresh, rings, valve job and bearings. I'm sure it will be enough for mom..

iceracer wrote: Just do a refresh, rings, valve job and bearings. I'm sure it will be enough for mom..

I don''t know why everyone is harping on one sentence so much. It's great that you feel as though it would be enough car for my mother to drive. The fact is that she won't be the only person driving the car. In fact, it's still my car as far as paperwork is concerned. I just decided it would suit my personal needs more to condense my fleet and buy a Z06, rather than having multiple vehicles for the types of motoring I like to partake in.

One thing about the performer RPM intake, it won't clear the stock hood with a stock air cleaner. You would need a drop base air cleaner. Just a thought if you are trying to keep it stock looking.

81cpcamaro wrote: One thing about the performer RPM intake, it won't clear the stock hood with a stock air cleaner. You would need a drop base air cleaner. Just a thought if you are trying to keep it stock looking.

Oof, didn't even think about that. 79 has the dual-snorkel, so that might be a deal breaker. Is the normal Performer that horrible? The RPM isn't going to cost me much (aforementioned trade), so I can at least start by testing clearance. If I had to, I could ditch the snorkel. Unfortunately, I powdercoated the base many years and already picked up new bellows/lid.

Mazda787b wrote:

81cpcamaro wrote: One thing about the performer RPM intake, it won't clear the stock hood with a stock air cleaner. You would need a drop base air cleaner. Just a thought if you are trying to keep it stock looking.

Oof, didn't even think about that. 79 has the dual-snorkel, so that might be a deal breaker. Is the normal Performer that horrible? The RPM isn't going to cost me much (aforementioned trade), so I can at least start by testing clearance. If I had to, I could ditch the snorkel. Unfortunately, I powdercoated the base many years and already picked up new bellows/lid.

Ditch the snorkel and run a drop base. Any intake worth anything is going to be too high to fit with the stock setup

Mazda787b wrote:

81cpcamaro wrote: One thing about the performer RPM intake, it won't clear the stock hood with a stock air cleaner. You would need a drop base air cleaner. Just a thought if you are trying to keep it stock looking.

Oof, didn't even think about that. 79 has the dual-snorkel, so that might be a deal breaker. Is the normal Performer that horrible? The RPM isn't going to cost me much (aforementioned trade), so I can at least start by testing clearance. If I had to, I could ditch the snorkel. Unfortunately, I powdercoated the base many years and already picked up new bellows/lid.

Normal Performer would only give up a few ponies over the RPM. A Performer on a 350 will run out of steam around 5500 RPM. You're going to need 6000-plus RPM to make over 350.

Its one of those matching component things. Match everything to your required RPM range and you'll be great.