Beginner questions!

[goatkeeper]

Hi,
We have a 55 2 dr. Chevy wagon we are gathering parts for. We are debating between a 5.3 new motor and a 348. Being Pontiac people we am not familiar with 348/409 technical issues. We have located a '58 long block (no spark plug cooling), but I have see that it does not interchange with other 348's. Is this a bad choice? Should we look for a particular year? Is a truck block better or are the 348's the same?
We will want a reliable 300+hp assembly. We probably will do some kind of fuel injection, perhaps a six pack intake with injectors and the carbs for air only. Are there good and bad factory exhaust? Do these motors have anything like Pontiac's long branch or Ram Air exhaust? No headers, preferably.
We would appreciate sound information. We like the idea of the 348 in the '55. It definitely would draw attention!
Thanks,
Jimmy

[Tom Kochtanek]

Jimmy:

Thanks for asking. You are asking the choir which song to sing, and most would agree that a "W" engine looks unique in a number of vehicles. A few guys here have Tri-5 installations, and you might be some info from those fellows. The ones I am thinking of are 409 builds, but a 348 has similar characteristics at first glance. Plus it can easily put out 300 plus horses. The 1958 components are unique to themselves, but so long as you have the block and heads you should be OK. The other stuff (intakes, exhaust manifolds, water pumps, etc.) should bolt right up.

You might need to make a few mods to get the 348 to fit your '55, but you seem up for that. If you attempt to feed that engine with a custom fuel injected system , you can certainly tackle these other challenges.

Stock the 348 puts out about 250 horses, so you'll need to get improved flow in and out of the engine to get 50 or more horses. Not too hard to coax those out :).

I'm sure others will chime in a give you additional advise and opinions. Anyone can buy a crate engine and fit it up, few have the good taste to put something classic and unusual in their rides. Good luck in your decision making!

Best,
TomK

[JimKwiatkowski]

Jimmy,I agree with Tom,you need a "W" Motor between the frame rails of your Shoebox.Everybody has a small or big blocks in there Tri-Five.
I have owned my 57 for 25 years and 24 of them years there has been a 409/425 in the 57.Do a search on installing a 348-409 in a 55,there has been alot of info written on this subject

[RCE1962]

Jimmy

Good advice from TomK.

A "W" would be an outstanding compliment to the 55 for sure.

Pontiac people you say??

Check this out!


http://www.bruneauperformance.ca/


RCE1962

[RCE1962]

JimK

I guess it takes me longer to post a note. Just saw TomK's response at the time of writing.

Jimmy

Take a look at the various threads throughout this forum. There a a number of members here that have 348-409s in 55-57's AND earlier model street rods! Very impressive cars!

Try the "Search" feature on this forum.


RCE1962

[goatkeeper]

Thanks for the quick replies! But, please give meat, not milk! What is the difference in the water cooled plug motors? Do they run hotter? Can't bore as well? Heads restrictive? Do we need to avoid these motors? What are the questions we need to ask? I understand that it takes a special boring set-up to bore the 348/409's. Is there other goodies like this a newbie needs to know? One head better than another? Will the 409 crank fit the 348 block? Does this rod/stroke ratio make a better combo? We enjoy driving our hotrods and cubic inches are not always the fix.
Here is one I forgot earlier...Do the 348 and small/big blocks share the same bellhousing bolt pattern? T56 tranny is a MUST! Don't like them automatics, Roy! Also, please answer the exhaust question...is there a good factory exhaust?
Thanks very much for the input!
Jimmy

[61bubble]

There are hi po 2 1/2 inch manifolds that came on the hi perf 348's and 409's. They are getting hard to find, but I think that show cars does repros at 8-900. someone correct me if that is wrong.

Adam

[Tom Kochtanek]

Jimmy:

Thanks for all the questions, you ask a lot of the basic stuff that folks new to the "W" want and need to know. Collectively the wisdom to answer your questions is held within this Forum of knowledgeable folks. I am not the wizard, just a guy with a couple of 409s and some 348s. But I'll try to answer your questions, and perhaps raise a few for you.

At first I read your initial post and saw "348" and "55 Chevy" and I thought "good combination". Now you ask some questions that lead me to believe you are thinking performance. So my question is: "How much are you willing to spend?" and "How much can you do yourself?". If you want GM cast exhaust manifolds that have the best performance, plan on putting $600 - $900 on the table for the back swept 2.5 inch 925-926 manifolds. There are repops of these, but they are priced around $899 as I recall. That's a lot to me for a set of manifolds -- I would rather buy the pre-bent header pieces and weld a set up from those. Heads are another example in terms of wide range of prices. The higher flow 409 high performance 690 and 583 heads run at premium prices ($2000-$3000 for bare sets) then add a grand for machine work and moving parts. The 348 heads are more common, less desirable, and look just like the high performance heads, but cost much less. Bare heads for 348s run hundreds of dollars, not thousands. The "333" cast truck heads are also readily available and can be had for around $100 a set needing to be rebuilt. Big difference in price and in performance.

Let me try to address some of the questions you posed, and I'll let others add to that.
What is the difference in the water cooled plug motors? Do they run hotter? Can't bore as well? Heads restrictive? Do we need to avoid these motors?

The 1958 passenger engine is probably the least exciting of all the "W"s unless you have a 1958 Chevy and are trying to remain original (I know this is not your case!). It is a lower performance (250 horses with the 4 barrel) build. Looks good, has some torque, not a lot of pizazz in terms of brute force. Do they run hotter? I don't know, maybe someone else does. I bet not.

I understand that it takes a special boring set-up to bore the 348/409's.

The deck on these babies is not perpendicular to the bore, and they are canted some 27 degrees from the 90 degree design of the SBC and BBC. You need a special boring bar that accounts for that angle in order to bore or to sleeve a "W" hole. Some older shops still have these boring bars, but they are not made anymore (I guess you could make one).

Is there other goodies like this a newbie needs to know?

You can bore some of these blocks out way beyond .060", unlike the SBC and the BBC. I have a running 409 bored .100", others up to .125". Get 'em sonic checked and look for minimal shift in the castings (check the cam area on front of the engine for indications of core shift).

Higher performance parts command much higher prices. You can get a set of 333 truck heads for $100 but be prepared to shell out thousands for a set of bare 690s or 583s (see info elsewhere on this site for differences in heads in terms of performance).

QB blocks (indicating that the engine ran solid lifters with big heads and multiple carbs) are more expensive than newborn babies :).

1961 409 parts are rare as hen's teeth. Use them to fund your childrens' college education :).


One head better than another?

Not on a doloar-for-dollar basis, but in general the bigger valved heads flow more and support higher horsepower ratings.


Will the 409 crank fit the 348 block?

Yes, and this is an inexpensive way to make a stroker out of a 348, as 409 cranks are readily available at fair prices. You will need stroker pistons for such a setup.

Does this rod/stroke ratio make a better combo? We enjoy driving our hotrods and cubic inches are not always the fix.

Lots of newer camshaft options for various applications, much better than the stuff available back in the 60s :). Most have found that stroking the crank wakes these babies up considerably.

Here is one I forgot earlier...Do the 348 and small/big blocks share the same bellhousing bolt pattern? T56 tranny is a MUST! Don't like them automatics, Roy!

Same pattern, with different starter mounting options (bellhousing or block mounting of starter?).

Also, please answer the exhaust question...is there a good factory exhaust?

Yes and they are expensive (IMHO). Get a set of 2.5" originals and you will spend maybe $250-$300. Get the swept back style and pony up with $800-$900. Not that much difference in my opinion. Want performance? Get or make headers :).

So tell us whether you want to spend less than $5000 or up to $10,000 on a rebuild and we can give you an idea what to expect.

Remember, these are just my observations and opinions. I'm sure others will add their perspectives as well.

Good luck with your decisions!

TomK

[rwagon57]

Interchange between 348 and 409. Almost everything except heads and pistons interchange. 409 heads (at least the 690 and 583 castings) won't work on a 348 block due to valve to bore interference. The 348 in my signature is a '58, so even they can be improved.

[johnnyrod]

I had my 348 bored at a local older machineshop and they used a newer machine and no special boring bar. Its a 1960 block. They had no problem doing the job. She runs great I might add. John

[goatkeeper]

Would like to thank everyone for their time in responding and the great info!
Jimmy