Hi experts

I'd like to boost the hp figure of my basic GM Goodwrench engine in my '76. I've thought about a new crate engine but just can't afford one, so I'm looking into upgrading my engine. I'm a complete noob with engine mods.

I like the idea of buying a performance package from someone like Summit, who've assembled all the bits for me. Their SUM-BB2 package looks pretty comprehensive:
http://store.summitracing.com/partde...128&N=700+150+

...but I've got some questions. Can you help?

My Goodwrench engine is a 4-bolt main block. I assume it's got a basic crank, rod set and pistons. Should I do anything to the rotating assembly before installing the Summit package to lighten, balance or strengthen it? Would I gain noticeable performance or reliability by changing pistons or rods or whatever?

What hp should I expect to get with the basic Goodwrench pistons and that Summit package?

What fuel would I need to run to prevent detonation? (I don't know what comp ratio I'd get with my existing pistons and 64cc chambers.)

Which carb would be best for my manual '76? The package contains a vac.sec 800cfm carb. Is that going to be right? (800cfm seems like a lot for a 350 engine to my noob eyes.)

Will the roller lifters and rockers fit in my engine with no mods? My engine was made in Mexico no more than a decade ago.

Do you think that Edelbrock Vortec Performer RPM Air Gap manifold will fit beneath my stock hood if I get a drop-base air cleaner?

Thanks in advance for any advice/experience/help anybody can provide before I venture into the unknown. (Are there any good books on this? )

 

Not an expert nor a guru.

GW Uni 350 w/ 64cc heads & 5.8cc x 0.028" gaskets won't quite make 9.5:1 scr. I dunno what cam's in that kit but it might be too big for 9-9.5:1. Whatever fuels a current gas Vauxhaul will work. Before you order this kinda stuff, You need to VERIFY what sort of lifter bosses in your block ... pull the intake off and take a look ... that'll tell the tale. If you KNOW what to look for ... you can pull a pushrod & peek thru there at lifter boss ... on a roller block the top of lifter boss is flat-milled ... but it's rough on non-roller block. I dunno, but suspect you'd have hood clearance issues w/ any decent size filter & Vortec RPM Air Gap.

 

Thanks for the reply, Jackson. That's helpful - it's good to find out what the potential traps might be. I guess I might be able to get help from Summit too but calling the US from the UK to ask dumb-*** questions isn't cheap.

 

As usual, Jacksons Right!
If your goodwrench engine is late model, it will be machined for OE Roller assemblies. You wont be using those link bar lifters or those pushrods. This is a good thing, the parts will be less expensive and easier to set up. If its a Late model Block you need to research Late model Roller assembly parts and setup.

 

If you want a safer choice with that engine, try this:

http://store.summitracing.com/partde...0&autoview=sku

It will get you a 9.0-1 compression ratio with that engine.

 

..... a few months ago (June '07? ), CHEVY High Performance magazine took the 290 HP crate-motor (verified before doing any modifications at 315 HP & 351 TQ ), swapped the heads to GMPP FastBurn heads, CompCams 270H, RPM Air Gap intake, 1.6:1 roller-rockers, and 650 Holley double-pump carb, resulting in 385 HP @ 5600 RPM, and 407 TQ @ 4200 RPM, on 91-octane gas (9.9:1 CR ), with 12" of vacuum at 800 RPM idle:
I believe the total cost of their upgrades were less-than $2000.

 

Here comes another stupid question... sorry:

How do I know whether it's a 'late model' engine? Is it down to the casting number, and can I compare my block's # with a list somewhere?

 

Thanks Glen - unfortunately mine isn't the 290hp engine. I'd be surprised if it's putting out more than 220hp with the 268 cam, the Performer intake and Holley carb I've installed in the past.
I need a more radical jump in power, I think.

 

Thanks for your suggestion, and apologies for the triple post.
Won't a low compression ratio limit the potential for hp?

I'm really shooting for something dramatic: 400hp+
Otherwise there's not much point for me in going through the hassle. If I'm going to strip down and rebuild the engine myself then I want to get to the stage where in 6 months' time I'm not thinking "...Wish I had more power."

Really want to do it right first time, even if I have to learn lots on the way.

 

I'm just guessing (and hopefully jackson can either confirm or deny my suspicions ), but I'm of the opinion that the 290 HP crate-motor is about the weakest offered by GM, at-least-as far as compression (8.5:1? ), pistons (cast? ), crank/rods (iron, regular-production ), etc., and that almost any SBC, making 8.1 compression would respond similarly with the heads/intake/carb, and survive quite-well at a modest 5600 RPM.


I found the original article, which states the 290 HP motor made 359 HP & 378 TQ with the swap to FastBurn heads (i.e. - NO camshaft change ), and 371 HP / 382 TQ adding 1.6:1 rockers, so the heads & rocker-arms-alone were worth 56 HP & 31 TQ with the original .450"/.460"-lift, 222*/222* duration cam:
I'm guessing if you could squeeze what ya got harder/tighter (higher compression ), you'd be happier with what ya got.

 

if you want +400hp copy configuration of a 385fast burn and add a LT4 hot cam kit --> 430hp@5800 and 430Ft.LBs @4000

 

Looking at gm performance parts engines the 260HP and 290HP
have flat tappit cams 76cc heads the 330hp,HO has a flat tappit
with 64cc vortec heads, you have to have the 355HP ZZ4
before they show a hydraulic roller cam.

I looked up the EDL-2099 that comes in the summit kit in my edelbrock catalog.
The package is 435 HP rated the cam is a retro fit (pre-87) hydraulic roller
cam. the cam is a performer RPM #EDL-2201.
the camshaft specs are.

.050 duration 234/238
advertised duration 296/300
lift 539/548
LSA 112

If you have a 350 this is way to much cam.

 

Looking at the other posts Im doubting your Block is OE roller machined, Goodwrench may use another Block than GMPP uses for 350CI crates? Only way I Know to verify is remove the manifold and see if you have the Bosses for the spider that Holds the OE roller lifters and keeps them from turning.
Anyway you slice it, it is possible to get 400HP and 400TQ. BUT thats really pushing the potential for a non racing 350 Block to its Limits. Depends on how you drove it But Your Crankshaft, Rods & pistons would be vulnerable to Destruction, I dont think a good engine builder would push for 400HP with your shortblock as it is.
Maybe 350HP and good low end torque would be more reliable and less expensive too.
The GMPP zz4 engines may even use the same Block as you already have? But they Bullitproof the build with forged Crank, Steel Rods, Alum Pistons and Mild roller assemblies Thats how they get away with Hi-performance power with a Good WARRANTY.
Maybe Someone will chime in with some definite info about what you have for a Block. It all starts There.

 

Here's a link to the Chevy HP article on the Goodwrench upgrade. I did this to mine and am happy with the outcome.

http://www.chevyhiperformance.com/te...ild/index.html

 

Repeat ... pull a pr & peek at top of lifter boss!Heck ... even ZZ4, HT383 & ZZ383 have cast (hyper) pistons ... as does 400hp circle track race motor (GM p/n 88958604). Some cheaper motors have cast cranks ... including 350hp 88958602 ctr motor. Just around here, there must be some 50 or more of those x602 circle track motors that get beat on real hard every weekend ... they last & last w/ cast pistons & cranks.

 

Hey, that's really interesting, Duke. Thanks for the link. I'd read that article before but forgot about it. I'm pretty sure they started with the same engine as mine so it's cool to see what they achieved. I think I'd stop before the supercharger though

I priced up the same kit as they used (TPS heads, XE 268H cam, Holley 750 carb etc.) and it comes to more than the Summit package, but not by much. At least I know it'd fit my engine. The dollar will continue to weaken against the GBP so by the time I'm ready to purchase it'll be even cheaper.

Thanks to everybody for the comments/suggestions. I really appreciate your contributions.

 

They are same eng, the 290 version has a bigger cam.