I have a '78... was an L82, but the PO replaced the engine with a GM Goodwrench 350 Crate and added side pipes (kept the exhaust manifold and all smog stuff except the cat). In order of lowest dollars/performance ratio, what should my upgrade priorities be for more power? Headers? Intake manifold? Heads? I will be doing the work myself.

Thanks.

 

First you need to find out exactly what you have to avoid wasting money.
What crate engine is it? Compression ratio? side pipes and manifolds? Auto/manual?

 

Seems like most of time ... when someone says "Goodwrench 350" they're referring to old pn 10067353 ... replaced by newer pn 12681429.

Both essentially an L48 with about 249HP ... cast pistons ... cast iron block, crank & heads ... but with 4-bolt mains.

Whether old pn or new pn: about 8-to-8.5:1 CR, 76cc conventional heads, dished pistons, 2-piece rear seal and a tiny .390"/.410" HFT cam.

*However, sometimes they mean the 290HP version pn 19355658.
Essentially, same as above, but with the larger L82 cam.

 

Thanks for the replies. The casting number of the engine block is 10066036. Hecho en Mexico.

I am almost positive that the intake and exhaust manifolds are from the L82. A lot of what i read said to open up the exhaust first, but it looks like to add headers i would need to add new pipes as well, and since its already got side pipes I didn't know how big of a jump I'd get with headers.

The PO did give me the old L82 engine. It apparently has a broken connecting rod, and I'm not sure how bad of shape its in. The cam might still be okay, and I could remove and use the heads but not sure if thats worth it.

 

Still has the same quadrajet carb too.

 

Sorry... And its a manual transmission

 

cn 10066036 could be several motors. Get numbers from block's deck stamp pad immediately in front of passenger head.

L82 cam dime-a-dozen. They have good forged pistons and forged crank ... well, good until it throws a rod ... box of chocolates ... open it up & see.

 

I think its
1M0722
4VP
Tough to make it out

 

quote from Mortec forum about a similar situation posted 2013:
... From the Engine Assembly Code you posted, 1M0521 4VP; 1= Chevy, M = Mexico, 0521 = May 21 (assembly day), 4 = 1994, VP Engine Suffix Code = 350 CID, 260 HP.

following that line of logic:
1M0722 4VP; 1 =Chevy, M = Mexico, 0722 = July 22 (assembly day), 4 = 1994, VP Engine Suffix code = 350 CID, 260 HP.

If that's so, seems you're sittin' behind a "Mexican L48"


https://www.mortec.com/forum/threads...-question.173/

 

You've already got true dual exhausts ... headers nor another intake not gonna do much with that low compression & teeny cam.

You need more compression and more cam ... they should be increased in concert. Those L82 heads won't increase comp; they're 76cc too.

aftermarket 62-64cc heads ... dozens & dozens to choose from ... hundreds of cams.

#1 --- Come up with a budget and clear desires/goals.

 

Too bad the L-82 is gone since the forged components of that L-82 motor are the basis for my rebuild/upgrade to my OEM 1978 L-82 and are really good as a foundation build. The forged L-82 crank and rods are in my L-82 355 on their 6th driving season and performing well with 50% more Gross HP than the L-82. Also, don't get get confused by the Gross versus net HP ratings of a factory L-82 versus an aftermarket crate motor since they are not the same. The factory L-82's were rated 210-250 NET HP while the crate motors cited are 249/290 Gross HP...not the same. A factory 220 NET L-82 is about 300 Gross HP and the factory 1974 L-82 rated 250 Net HP is about 330 Gross HP like a 71 LT-1, very similar.

Answering your question, the best way to get more HP from your low compression crate motor are Long Tube Headers/true 2.5 dual exhaust, Cylinder heads (64 CC will give you a 1 point compression bump or 58 CC vortecs 1.5-1.75 compression bump) along with a performance camshaft sub .500 lift/moderate duration-lots of choices). These 3 changes will easily get you 400 Gross HP......

 

1. The best aluminum heads you can afford. 195cc flow 64 cc chamber Any engine or cam will benefit from breathing easier
2. A good cam, flat tappet is cheap but needs specific oil, all the parts to convert to roller get expensive but its a lot better and any oil works
3. Better ignition system if you arent already some type of HEI
4. EFI

 

I still have the L82 ... it has a broken connecting rod. Not sure of the extent of the damage. Is it worth rebuilding it for any reason other than to keep the car original? If I'm swapping heads and the cam, is there a point?
I'm interested to hear more about what you've done.

 

I'd say I'm willing to put $1k into the upgrades.

 

Do you have a reccomendation on the heads?

What is the specific oil it would need? And how much would you estimate the cost of converting to rollers?

 

trick flow makes a nice 175cc head, afr 180
Roller cam conversion around a grand...used intakes are cheap, 1-5/8 headers work well on a 350.
What rear end gear, 3.70? Even a GM Hotcam would work great, they arent much at summit. A 650dp and youre set , ought to have a strong runner that will have good manners and be maintenance free

 

$1K ain't gonna do heads & roller cam setup

getting hard to find these days
https://www.ebay.com/itm/sbc-Matchin...YAAOSw4Ohcm-Gr

 

those $640 heads

a cheap Hydraulic Flat Tappet cam & lifter kit from summit (K1103 or K1104 or K1105) about $112

those heads don't have rocker arms or rocker studs: need all ... can spend under $100 or over $300

need pushrod set ... spend $30 to $130

need head & intake gaskets spend $40 to $140

adds up quick

 

What cams could I use with the stock hydraulic lifters?

And would those 58 CC heads require high octane fuel?

 

OP has a decent basic crate motor so use it.......add a Comp 268H cam and tune for it. Save money for the next upgrade.