I am looking into building a pontiac 350 for a guy and need some help
from a pontiac expert if there's any in this group.
1st, are the pontiac "big blocks" all the same block?
I notice the 350 and the 389 share the same stroke, could a 350 block be
bored to become a 389?
2nd, anyone know where to find pontiac performance parts? The usual
suspects only have the basics, heads (edelbrock performer) gaskets, etc.
I'm looking for some decent forged pistons, good aftermarket rods etc.
everyone but you knows where to find performance parts......
but....because you can afford a computer, an internet connection,
have shown the wise of mastering typeing, shown you have
remedial abilities in engine size comparisons, and yet have NOT
obtained the remedial ability of "Google" everything.........
call the local AutoZonedOut store........if money is
~sips his crownroyal...takes a toke.....and ponders all
he could of been if he hadn't dropped outta school~
Yes, I'm quite capable of doing a google search, but thanks for the
advice. I thought asking for a SUGGESTION of a good place to buy parts
might yield me some leads on where to look from someone in the know,
instead of wading through the hundreds of hits returned on a search.
Apparently that was asking too much.
2....are you not happy with the lead i gave you?
3...you did NOT ask too much.
4...you're exhibiting the traits of a troll now.
5...number 4 is an opinion...based solely on the fact that YOU
suggest that you are capable of using a search end, yet you
wasted good hyperspace by asking questions whose answers
are readily available, requested resources that are KNOWN to
exist by those with menial search capabilities, and........
the fact that you bothered to reply to me in a suggestively
authorative and hostile manner.
6....i'm haven a hoot of a time....bout you?
~sips his mushroom tea......and pours you a stiff one....~
Pontiac V8s are Pontiac V8s; externally good luck telling a 326 from a
No; you'd be well into the water jacket. Just because the block is
the same basic dimensions and architecture doesn't mean that they used
the same casting cores for all engines. Even trying to overbore a 389
to a 400 isn't likely to work.
What are you trying to accomplish, what's the budget, and why a 350?
Unlike in the Chev world where the most common small-block buildup is
a 350 (and big-block buildups are expensive so everyone goes with the
small-block buildup), in the Pontiac world a 400 is the most common
performance build, and the parts for 400s are the cheapest. The next-
most-commonly built engine is the 455: not necessarily because it's
the most easily-found engine these days (production ceased after '76)
but because there are lots of cubic inches to work with.
I don't even know how well a large-valve aftermarket head would work
on the relatively small-bore 350 due to valve shrouding. I can't say
that I've ever heard of anyone doing this.
As far as parts go, there will be very few parts listed as 350 parts,
although most 400 parts will indeed work on a 350. In fact I'd think
that *all* 400 parts, other than the block, pistons and rings, will
work on a 350 (although like I said the large-valve heads may be
That being said, Pontiac performance parts are expensive. The stock
rods on a 350 will not be anything to write home about, and may not
like to be revved much above 5500-6000 RPM. With some exceptions that
you're not likely to encounter, Pontiac rods are cast and not forged,
and don't hold up under high RPM. On the other hand, you don't have
to spin a 455 much over 5000 RPM while still making lots of
Now, if you and the guy are still keen on building a Pontiac engine, I
commend you! (Sure you can drop in a Chev engine and make it work,
but the Pontiac magazines won't feature your car, and Pontiac owners
will come 'round and sniff. Of course you may not care what Pontiac
Sources of further information:
Magazines: grab a copy of the latest Pontiac Enthusiast and High
Performance Pontiac. Both will have lots of ads for Pontiac-specific
parts, and Pontiac engine builders.
shows the latest Pontiac engine handbook; should give you tons to
think about. (If you come across cheap older copies of Pete
McCarthy's books, or the H-O Pontiac Performance Handbook, they are
worth picking up although they pre-date the "modern" Pontiac
performance world with aftermarket aluminium heads, aftermarket
blocks, cranks, and rods, etc.)
Online: Performance Years forums at http://forums.performanceyears.com/forums /
are recommended a fair amount (I'm not much into web forums of any
kind). Usenet groups alt.autos.camaro-firebird and alt.autos.pontiac
may help you a bit, but the quality is kind of not there any more.
If you're really keen you (or the guy) could join the Poncho Power
mailing list which you can find by googling....
--if you are building a Pontiac engine for a Pontiac car, I commend
--however you're much better off starting with a 400 or 455; the
results will be better enough to make it worthwhile acquiring the core
400 (455 will cost more)
Oh, yes, if come across www.pontiacpower.com and are enthused by the
info there, I'd strongly suggest you ask around on the forums/mailing
lists for opinions about this one particular Pontiac performance
shop. I have heard plenty of second-hand stories and they all trend
very strongly to one side of the the satisfied/dissatisfied scale....
Thank you, I had a feeling that might be the case but wasn't sure.
Basically, a street driven pontiac 350, 350+ HP on unleaded pump gas, no
nitrous, blower etc. Pretty simple really. As far as why, because the
customer is always right, I'll build whatever they want.
I notice it was a rather small bore for it's size, and the same as a
307/283 chev, which I have built several, and they don't seem to suffer
from the valve shrouding like the 305's etc. do.
I tend to "build" any motors first on dyno sim software, and at the
horsepower level he's looking for, 5500 would likely be higher than even
necessary. Are the pontiac rods the archilles heal of pontiac motors
like they are chevy's? ARP rod bolts considered a necessity then?
This was exactly the kind of info I was looking for. I mainly build
chevy dirt racing motors and have lots of sources for parts on those,
this was the type of insight I was looking for, thank you.
Probably moreso that with Chev engines. Chev rods are forged; Pontiac
rods are cast. The bottom end will start to go egg-shaped at some RPM
Here's someone else's take:
The main reason that people don't build 350s is because for the same
less money spent on a 400 you will get 14.3% more torque out of the
all other parameters being the same. In the past, 400s have been
as plentiful as 350s so it just didn't make any sense to spend more
money for less power. Nowadays with all Pontiac engines becoming
increasingly scarce I think we will see more 350s being built as
will build what comes in the car they buy rather than spend a bunch
time and several hundred dollars tracking down a 400 or larger
As real estate values climb, wrecking yards get squeezed out and with
stricter emissions laws all over the country, the old cars get
before people can scavenge their parts, not to mention that every
there are fewer 400 blocks left in serviceable condition.
As for a 350 horse 350, it shouldn't, in theory, be all that
The power is in the heads. If you have heads that flow well and a
decent compression ratio, then the rest of the parts for a 350/350
Of course, heads that match a 350 then become a problem. The big
heads have their own set of problems when run on 350s. The valves
are too big for the bore size. Chevy smallblocks don't have 2.11"
intake valves and 1.77" exhausts. They have 2.02"/1.60" valves and
to do very well with that valve size. The Pontiac exhaust valve is
plenty big enough in the small valve heads but it would be easy to
increase the intake valve to 2.02". A good street porting job and
heads should flow plenty. Then there's compression of course. The
high compression 350 Pontiac built was the '68-'69 350 HO. Heads for
those are rare. Most small valve heads don't have small enough
chambers, and as mentioned, the big valve heads have valves that are
big. They'll work, but they're bigger than necessary and do suffer
shrouding. That said, the KRE 65cc heads would be a great choice on a
So, it's definitely more difficult and takes more research and
to build a 350, which means more money, too. Still, I'm willing to
that in coming years you'll see more of them, and like I said, in
a 350 horse 350 should be relatively easy, if you have the right
and don't mind spending a little more to get less torque.
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