350 Overhaul

by 76 Malibu Sun May 31, 2015 11:17 am

My original L65 350 2-bbl is running well, but it's far from a powerhouse. The car has about 100K miles on and still seems to be fairly tight. I was thinking of getting an intake, carb and some new heads, but I figure with that many miles on it, it's probably due for a full overhaul.

I was thinking of getting a new set of GM Vortec heads, 062 casting, a comp cams XE262 cam, Edelbrock Performer Intake, maybe a Holley 600 and a decent set of headers. I am thinking of something like a 350 hp street engine. Will the stock 2-bolt block, rods and crank be fine for this build? Or would I be better off looking at crate engines?

It's my understanding the Vortec heads would need to be modified for height lift cams. The XE262 has a .470 lift with 1.5:1 rockers, so would I need to mod the heads for this? How about the press in rocker studs? Should they be upgraded? What should I use for rocker arms?

I am looking to do a good strong, durable, reliable street engine that still gets decent mileage. My car is exclusively used for street driving, and sees lots of highway use. I am thinking of eventually installing an OD transmission too, so I can put some steeper gears in the back.

Any advice of the engine build? Any experience with that cam or Vortec heads?

Looking for any and all feedback.

by pila Sun May 31, 2015 12:02 pm

Hi Tony
Many folks don't get excited about using a 2-bolt block for up to 400 HP. If you use flat-top pistons, ( yours are likely dished tops) the compression ratio will come up a bit to help the cam you mentioned.
I'm not familiar with the Vortec heads as far as valve lift comes into the picture. I've been running the Comp Cams Magnum roller tip rockers since they first came on the market, with no problems.
Going to an OD transmission, a 2004R comes to mind, with rear gear ratio of 3.73:1 makes a big difference in performance. The 2004R will not need a new drive shaft to be built, which is a plus too.
A Holley 650 CFM would be a touch better for a 350 with the mods you mention. Headers are the cheapest HP increase in a Chevy it seems !
Not sure how much power you can get with that cam though, but with the rear gear & OD trans you will sure feel decent power for street fun !

Have fun !!

BILL

by brownbomber77 Sun May 31, 2015 2:35 pm

I have a 262 for sale....but idk much about Chevy engines.

by Joe73 Sun May 31, 2015 2:51 pm

I'd have no problem using your original 2 bolt block as long as it checks out good.
Before I'd put on new heads, manifold, etc. I'd do a hot compression check to see what you have. Each cylinder has to be within 5-10% of each other on the compression readings.
If the readings are not within spec, then go for the rebuild of your block. Crank and rods can be checked and reused if good.
If you go for the rebuild then make sure the pistons you choose have the correct compression ratio with the head CC volume you choose.
Look for a cam that makes good power low in the rpm range since the car is street driven. You'll be happy you did instead of having to scream it to make power.
Also keep the headers primary size to 1 5/8" max. You can even go with 1 1/2" primaries. Both will add to low end power. And I wouldnt go larger than 2.5" exhaust pipes since you wont be making over 400+ hp. You would also be happy with a 2 1/4" system. http://www.hotrod.com/how-to/engine/ccrp-9812-2-quarter-inch-exhaust-3-inch-exhaust/

Lots of things to consider and going to big can really hurt performance. I see most guys put in all the biggest stuff to make power but then complain when it doesnt perform quite well on the street. Go for low end power.

As mentioned above, some nice 3.73 gears and a 200r4 will really wake things up even with your stock engine.

by 76 Malibu Mon Jun 01, 2015 10:25 pm

Thanks guys good info here. My car already has 2 1/4 duals on it but other than that is basically stock. It looks like from reading on the internet I'd probably have to do some minor mods to the Vortec heads for a cam with that sort of lift.

How about the pressed in rocker studs? Are these something that becomes an issue on a build like this?

by Joe73 Tue Jun 02, 2015 6:10 am

Pressed in will be fine with that lift. Just dont put real heavy springs to gain higher rpms.

by Dinomyte Tue Jun 02, 2015 8:51 am

Remember that by the time you break a main bearing cap you've broken a whole lot of other stuff in the process regardless of 2 or 4 bolt. . . I too wouldn't worry about the 2 bolt block for what you've described.

by Joe73 Tue Jun 02, 2015 10:22 am

Im running my original 2 bolt block. If I needed a 4 bolt block and my block was still good, I'd opt for "splayed" 4 bolt main caps. No need for a 4 bolt block unless you'll be pushing good power and alot of racing.

by BBMALIBU Tue Jun 02, 2015 10:25 am

Consider buying a Crate Motor, you may pay less for more.

There are plenty to choose from; GM Performance, Blue Print, etc...

http://www.blueprintengines.com/

by 76 Malibu Tue Jun 02, 2015 8:50 pm

Thanks guys, great information. I haven't ruled out a crate motor, once you factor in all the machining costs and whatnot I might be further ahead. From what I have read online it seems like a 2-bolt block should be fine. Like I said, this is a street car, it will see some fun driving , but no racing. I just want a strong street performer.

Any other opinions, please feel free to chime in!

by Joe73 Tue Jun 02, 2015 9:11 pm

Crate motor might be a good choice. My car was running in the 13's with my original 2 bolt. Should be way better with my new setup. And with 4.10s my motor is always screaming. I can take off from a light in 4th gear with no chugging.

by 77mali Tue Jun 02, 2015 9:20 pm

After my "mild rebuild" that took waaaay too long, I can tell ya that a crate motor would be a great option. Next time I'm getting a turn key set up- drop it in fire it up, drive it like you stole it. LOL

I have a 262 comp "XE" with Vortec upgraded heads/intake...etc... I like it but it wasn't cheap. You may want to look into LS motors also maybe even a good used one- good power for not too much $$$. Few guys here have done them on their cars and seem real happy. Myself I like old school- with carbs, mechanical fuel pumps, etc., nice & simple. The set up your wanting is about 350 horses and that cam puts out a little over 400 ft lbs- transmission & torque converter is another consideration when upgrading from a "stock" 73-77 V8.

by pila Tue Jun 02, 2015 9:39 pm

Jegs has some GM crate engines at good prices. Check them out. Better that building your own, unless you want the experience & pleasure of doing it yourself, and have all the special tools to do it.
Machine shop costs can escalate the total cost of a rebuild too...

by BBMALIBU Tue Jun 02, 2015 9:59 pm

Something like this might fit the bill (all new); perfect for all around everyday driving.

http://www.summitracing.com/parts/nal-19244450/overview/

Stout and dressed to run the streets, Chevrolet Performance 350/290 hp deluxe crate engines offer the best value on an old favorite. These all-new (not rebuilt) engine assemblies feature 4-bolt mains for strength, smooth hydraulic camshafts, and durable aluminum pistons, making these small blocks perfect for that first hot rod or father/son project. Plus, the deluxe package means that you get even more value for your dollar with the addition of a high-flow aluminum intake manifold, gaskets, installation hardware, and chrome dress up parts. They add a shiny, finishing touch to these 350/290 hp crate engines. Go with the affordable performance of the classic V8 perfectly dressed--Chevrolet Performance 350/290 hp deluxe engine assemblies.

This engine has the pre-1986-style 2-piece rear main seal and will not accept Chevy Performance roller lifters. Designed for use in vehicles with a GVW of 6,000 lbs. or less. This engine is not designed, nor intended to be used in any marine applications.

Designed for pre-1976 street vehicles or any off-road vehicle. Engines installed in vehicles registered and normally operated outside of the United States carry no warranty.

by 76 Malibu Thu Jun 04, 2015 9:40 pm

I'd probably want to take it a step above that engine and step it up to something with better heads and cam. GMPP does have some awesome packages so I will have to price out some engines and figure out the rough costs to build my current 350. I'd kind of like to keep the original engine in place since it has been so dead nuts reliable and still runs great (just did 1300 miles without a hiccup).

by BBMALIBU Mon Jun 15, 2015 1:42 pm

So what's the verdict, inquiring minds want to know.

by brian74montecarlo Tue Jul 14, 2015 7:41 pm

i slapped on a elelbrock 2701 ( performer eps ) and 600 cfm manual choke carb expecting to wake things up from the factory 2brl was on there - sadly there was hardly any performence gain - that is until i added patriot clipster headers - not quite long tubes but slightly longer than "shortys" but still give you plenty of room to run the tubes with no underhang of exaust on the car - ground clearence was super important to me on that decision - but yeah the factory manafolds with air tubes in there were choking off my engine. now with the clipsters on there it is much much more fun to drive Smile

note how far the air tubes stick in to the heads....
second pic you can just make out the collector down under steering linkage to get a sence of the size of clipsters on my car.
350 Overhaul 689_zpsujfetjdw

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