need 348 rebuild advice

[carlalique]

Last week I dropped off a 60 348 HA engine for rebuild. This is my first rebuild of a 348 and would appreciate some experienced guidance.
This engine is planned for a low buck 36 Chevy rat rod. I paid $600 for the long block and have the following info after teardown. The cylinders measure .006 to .008 wear; mostly in the upper portion of the cylinder. Ther were no broken rings on original pistons. Can I successfully hone and re-ring or do I need to rebore .030?
I figure about $500 extra cost to rebore vs. hone because of new pistons, rebore, press pins, etc. This engine will probably only see 5,000 miles over next 5 years. Can I save $500 or do I need to rebore?
Is there any commonality in parts between the 348 and other Chevy engines; specifically valves, springs, rockers, studs, lifters, push rods, timingchain? Summit and Jegs don't show 348 stuff so if there is no interchangeability do I need to order only from Showcars or ?
Can you use standard chevy stamped steel roller rockers or are they specific for the 348?
Read some thread that dicouraged hardening of seats do to possible waterjacket penetration...will I be ok without hardened seats?
Can a geardrive be used in lieu of chain....any testimony, problems or machine work required for clearance? Cover clearance? Brand?
What is the best cam to use with stock 9.5:1 pistons.
A couple of the rockerstuds are worn and need to be replaced, should I go press in or screw in?
Sorry for all the questions; your feedback will be most appreciated.

[carlalique]

Over 34 viewers yet no response to my inquiry. I'm new to this site; hope I'm not asking stupid questions. Hopefully someone out there will share their years of knowledge of the 348.

[CDNpontiac409guy]

Carl... I guess I'll be the one to open the door to this:dunno

I think the problem is, your goal seems contradictory.... :dunno
On one hand, you're asking if you can re-ring, using your original pistons...
on the other, you're asking about using a gear drive:eek: :dunno

If this is for YOUR car, and it is getting light duty use... and you are being dollar concious ( who isn't ?! )... then I would say, by all means... re-ring it:coffee:


The damaged rocker studs ?
Pull 'em out, and press in new ones.

You want rockers ?
So many guys are going roller rockers... good used stock rockers are very available.

I would try to acquire a set of steel shim head gaskets, so you can retain the 9.5:1.

With that, because there are no valve reliefs in the pistons, you are limited on cam... but that's fine... we're not trying to break the bank.
So... a good modern cam profile... approx .500" - .520" lift, 212-220 duration @ .050" ( 260-270 advertised dur ) will work nicely. This cam can be used with a good set of single springs... no machining required.

Parts ?
Lifters, oil pump, rod bearings... regular SBC and BBC

I would recommend a Cloyes True Roller timing set.

Do a simple rebuild of the heads, and you're on your way.

That's one way to do it... MAYBE $1200
If you want to get in there and build a "right on" engine, enhancing the power a bit ( short of a stroker ), then you're looking at around $4000.

oh... and I don't believe in replacing the valve seats:nono1:

[Ronnie Russell]

Sorry I over looked your question, but it worked out good for you cause that Canadian guy addressed everything and as I far as I am concerned, He nailed it. Please keep in mind that Aubrey suggested those cam specs. for a reason. Do not try to get more aggressive than the specs. he suggested. A good old fashioned re-build with a few upgrades. This type of re-build is not discussed much in this forum, but would work great for a majority of street only cars. New rings will seal and work good with the .006 to .008 you have, until the rings get some wear after 20,000 to 30,000 miles. So with your plans, you can expect to tear down for boring the block in 20 years. :rofl Use small block oil pump, Melling IS 55A oil pump drive rod, sb fuel pump and sb drive rod. 2 1/2 exhaust manifolds(truck pieces work good) if possible. 3x2 carbs would look good on your Chev. Intakes are reasonable, would need to find 3 good carb cores for rebuild. If you go in that direction, our own "Fatride" can give advice on jets, squirters, tuning, linkage, etc. Nobody better. If you go single 4 bbl, try to find 409-340 intake which will allow you to use afb with correct gasket, and not have to use big ugly adapter. Stock points type distributor wil be fine for your application. Good luck with everything. Should be a neat car when you are finished.

[carlalique]

Thank you Aubrey and Ronnie for your feedback!. Yes I was hoping to save a few bucks by re-ringing vs. new pistons and rebore. On the other hand I'll probably waste money on unecessary items like Mooneyes finned aluminum valve covers. That was my reason for the question on the use of a gear drive vs chain....I want it to sound bad even if its not, if you now what I mean. Any clearance or use problems i I wanted to go gear drive?
Still not sure from your posting if 348 rockers are unique to the 348? Can I install used small block chevy roller rockers with 3/8 studs? Or do I change all studs to 7/16 and use big block rockers?
I also need one bit of clarification on cam specs as I am getting conflicting info; specifically: ShowCars told me not to exceed .458 lift without checking clearences. You all are telling me .500 to520 is ok; please explain.
I know where I can purchase a complete 3x2 setup for $650. Another option is that I currently have a nice 2x4 409 aluminum manifold...will it fit? Thanks guys.

[CDNpontiac409guy]

I'm sure we'll get some other guy's ideas here too...


I've run this hyraulic cam in the EXACT same engine combination you're planning. 4 years now... shift at 5400.
Lift: .520"/.525"
Advertised duration: 268/270
Duration @ .050": 218/224
Ground on a 110 centerline.
Approx .080" piston to valve clearance in the intake... exhaust has LOTS ( far more critical ). Spring pressure is 110 on the seat, 270 open.
If you were to get this cam on a 108 lobe centre seperation, it would have a good "attitude" at an idle ( that "bad" sound:deal ). Piston to valve would likely tighten up to .070"... which I have found to be no issue whatsoever. Again, exhaust clearance is more of a concern.
Your peak RPM would likely reduce to say, 5200... but it would pull HARD in the mid-range:deal .

Roller rockers ?
Big bucks... marginal gain.
There ARE W block specific roller rockers available for the 3/8" stud. Just put them on. Myself... I'm partial to the Crane P/N 15750 aluminum 1.7 ratio versions, but you'll lose about .015" lift ( but that WILL help slightly in your clearances ).
Stock stamped rockers ARE specific to the 58-65 W blocks.

ShowCars ? Have been doing this a long time... and have many EXCELLENT parts for engine restoration.... but ask them if they'd race me;) :p :rofl
HEEE HEEE !!!

oh... the reason that a modern cam such as the one above, clears, when old hot rod cams don't, is because of the generally shorter seat timing. Keeps vacuum up, and even provides better fuel economy ( tighter lobe centre sep does not:doh ).

"Wasting money" on Moon Eyes valve covers ?
naaaaaah.... ya' gotta look cool:deal

A triple 2bbl does look good, and set up right, really works. Not a lot of money either.

For noise.... proper tube headers are MANDATORY:beerbang
You won't need no stink'n gear drive:rofl :rofl

[Ronnie Russell]

" I'm sure we'll get some other guys ideas here too." Maybe, but I would be surprised. Aubrey covered everything with explainations and logic. I would sell the 2x4 set-up and invest in the 3x2s. Rat rod with Moon Eyes vavle covers and 3x2s , yep, yep, yep!!

[oldskydog]

Don't know if it matters to you but if your block is an "HA" suffix then it originally came with 3x2's and turboglide trans in the 280 hp version.

[blumun53]

I will buy your 2x4.
Rockers, etc---I used 59 model 348 heads on my 409. Used BBC roller tip rockers on BBC screw-in studs. Buick 455 valves were used, AND new seats were installed by Wayne Calvert Precision Engines in Denton, Texas. Absolutely no problems. I ran a . 524/544 cam. Again, no problems. The engine pulled good, revved very nicely and sounded great. Shortly, I will have a 3x2 set-up available for sale (59 model). But I want to get it all fixed up and pretty first.:cool:

[jim_ss409]

As usual I think Aubrey's absolutely right about the cam, especially the part about getting it ground with 108 lobe centers. It's the overlap, and also an early exhaust opening, that gives you a rough sounding idle. High compression ratios also help. Most cams have a lobe separation that falls in the 110-114deg range. And that's fine, but if you want a meaner idle you can go with more duration. But as a result you start to give up low end torque. By tightening up the lobe separation to 108 or so you open the intake valve sooner and close the exhaust valve later. That increases the amount of time that both valves are open at the same time. (overlap) And it's that overlap that's mostly responsible for the rough idle. The tighter lobe separation also gives you more low end and midrange performance. Having a cam with a little extra exhaust duration also helps get you the choppy sound because the exhaust valve opens a bit earlier while there's still a fair bit of pressure in the cylinder. So when it opens the exhaust note really pops out. And it's even better if you've got lots of compression. Most cams are designed to be installed about 4deg advanced, so if your lobe separation angle was 110 it would install at about 106. If you want to get the most benefit from the tighter lobes it's best to try and make sure you get the full 4 degrees or even 5 or 6. Another thing that seems to give a car a good sound at idle is big tailpipes. A set of 3" pipes at the end of the exhaust system will lower the pitch of the exhaust note and make the engine just sound bigger.
Comp Cams has a new line called Thumper cams designed to give that big cam sound without sacrificing drivability too much. I see that they're ground on an even tighter 107deg lobe separation angle. http://www.thumprcams.com/
Aubrey might know if 107 will clear your pistons. He might also be able to get the cam you need since it'll have be a custom order,,, they don't list Thumper cams for 348's and 409's:cry Here's a link to his site... http://www.bruneauperformance.ca/

[models916]

Good luck finding a Gear Drive for the W engine. Pete Jackson discontinued his a while back. Ebay getting outragous prices when they show.

[tripowerguy]

If you go a big cam be sure and look at the valve guides in relation to the lift. make sure the keeper doesn't hit the top of the valve guide at full lift. It would be a rare find if you found a gear drive for a 348. Also to be clear you need push rods and rocker arms for 348 or 409. If you use big block 1.7 rockers you need to use 7/16 rocker studs and small block rockers are 1.5 ratio. 348/409 rockers are 1.75 Roy