I finally found some heads "locally"for my 69 350. I picked up a set of #17s for $100! Based on my research this is would be my pick for 350 heads so I'm pretty happy. Why you ask?
My original #47s, which I would have been happy with, must have developed issues and were swapped out somewhere along line for #11s. For all you non 350 guys that may not mean that much but understand you are moving in the wrong direction in terms of compression and you need all you can get in a 350. According to Pontiac's own numbers the switch from 1968 #17s to 1969 #47 to 1970 #11s gave up 10HP and a full point of compression. The #17s tend to cc at 79-80 although advertised at 72. The #11s tend to cc at 85+. (cc not advertised! hmm) Sorry for the history lesson i'm a history teacher. I can't help it!!
The #17s I got reportedly came off a running 68 350 although that was 10 years ago. Regardless of their current state my intention was never to slap them on and go. My intention was to take them to the machine shop and make them like new. Now for my very delayed question. I found what I have heard is a reputable machine shop. I'm not looking for porting. What do I need to know before I walk in there and say "please make these like new and here is my wallet."?? I always like to at least appear like I know what i'm talking about. I do plan on having the presses in studs replaced with screw in. My eventual mild cam choice and HP goal don't dictate that but seems like good idea and not that much money.
For the screw-in stud upgrade, you'll need a set of ARP 290-7201 studs. These have 1/2" x 13 bottom threads. The existing press-in stud holes must be tapped for these threads. I've read that the bottom portion of the studs are about 1/8" too long & must be ground shorter.
Most agree that even for a mild street build, it's a good idea to upgrade to one piece stainless valves. Stock Pontiac & most cheap replacement valves are said to be made from 2 pieces, welded together.
If you plan a lot of driving, many say that you need hardened valve seats, at least for the exhaust seats.Then there are some who say they have been running without hardened seats for many years.
Many say you need to have new bronze guides as well as good valve stem seals installed.
Obviously, you'll need new valve springs to match the cam you'll be using.
Will also need to tell the machinist how much you want cut off the heads, to increase compression. Most say you can safely take at least .050 odd a virgin. It's best to have the same amount taken off the intake surface of the head as is taken off the chamber surface. This will help to maintain the intake bolt hole alignment. Some say to cut the intake instead. But, if you cut the intake, it may not fit other engines, down the road. Also, if you decide to try some other intake, it would probably also have to be cut down to fit. So, it's just better to cut the intake surface of the heads, rather than cut the intake itself.
Some go with larger intake valves. Most say that the 2.11 Pontiac size intake valves are not needed for a mild 350. Stock size valves will be fine. But, there are many sizes available.
You may also need a new heater hose nipple for the passenger side head.
Don't have any #17 heads, & can't find any good pics right now. But, if they don't have the end exhaust manifold bolt holes(many Pontiac heads did not), it may be a good idea to have the holes drilled & tapped. That way you can run headers or exhaust manifolds that require the end holes.
Interesting comment on stud length. I had a set of heads with screw in studs and I had to add washers under the rocker nuts to be able to adjust them. Somebody did a bunch of work to them including tapping the stud holes from what I could tell.
Yeah, I think the upper length of Pontiac screw-in studs is 1 3/4". So, if you use 7/16 studs which are longer than 1 3/4", and use poly-lock nuts, you may need either longer poly-locks or hardened spacer washers.
Good info. Thanks!! I guess I need to think about a cam. Something I know nothing about. I understand the differences but generally not why somebody actually chooses a specific one. My end goal here is to put some good pop in the 350 not try to get all I can out of it. The engine needs a rebuild and I'm sticking with it because it's original to the car. Bore .030 over. swap to 4bbl. Add Dual exhaust and long branch. I'm thinking 3:08-3:23ish posi rear. I'll bet after that she moves out quite nice. At least enough to leave a little patch at the Dairy Queen!
(2) The Summit cams are probably the cheapest choice. The 2800 will have a smooth idle & plenty of low end torque. The 2801 is probably one of the biggest cams I'd try in a mild street 350 build. It would probably work better with closer to 9.5 CR.
(3) Don't think I'd wanna run anything smaller than a Melling SPC-4 or SPC-5, which are clones of the Pontiac 066 & 067 cams. The 066 was used in the low CR '74 GTO 350 engine. The SPC-7 is a clone of the Pontiac 068 cam, which was used in some of the '69 350HO manual trans engines. It is similar to the Summit 2801, but has less lift.
(5) If you don't mind paying more, the Crower 60240 & 60915 look decent. For some reason, Crower seems to think their cams are worth more than other big name brands.
Pontiac guys also have different opinions about which lifters to buy. Some say the cheap Summit lifters have worked OK for them. Some say their suppliers change, therefore you may get lower quality lifters.
Paul Spotts is a respected Pontiac engine builder. He recommends the USA made lifters which he sells. They're some of the cheapest available, at $59 shipped.
Well, as usual, this link won't work on this forum. But, you can go to Ebay & type in: new us made lifters oldsmobile pontiac. The seller is listed as fbpaul. He is Paul Spotts of Spotts Performance.
There is a way to run a slightly larger cam, but still have a decent idle, vac, & low end power. That is to use Rhoads lifters. I did this in my 455 bracket engines by using an 041 clone cam, with Rhoads lifters.
This might work for a 350 street engine with cams in the 220° @ .050 lift range. The first one that comes to mind is the Lunati 10510312.
Rhoads would also give the Summit 2801 cam a bit more low end power. Might be a good combo for a 350. Original Rhoads lifters are available in 2 versions. One version has a groove to supply extra oil to the cam lobes. They call that option Super Lube.
Rhoads lifters do make a ticking sound at very low rpm. Some can't stand the sound. My cars always had open headers or loud muffs, so the ticking never bothered me.
Hylift Johnson "R" lifters have a slight bleed down at low rpm. But, not as much as Rhoads. So, some Pontiac guys recommend them. Paul Knippen is a Pontiac guy who can order Hylift Johnson "R" lifters for you. He may even have some in stock.
I've been playing with the Wallace Racing compression calculator, a very useful tool by the way, and it looks like at 80cc at .030 over I should get 9.18 compression. That would be just about perfect! Only variable I don't really understand is deck height so I left it at 0. I know "what it is" I just don't know what to expect in the car and therefore what figure to put into the calculator.
RE deck height: You gotta pull your heads and measure it. Important info if you want accurate calculations. Also include any valve reliefs on the pistons.
Not sure if anyone mentioned this, but have your machinist magnaflux the heads prior to any work.
Have him CC the heads before you decide how much, if any, you want milled off. As in post above, advertised and actual chamber volume can be quite different.
I'd recommend hardened valve seats . I have seen, with my own eyes, exhaust valves that were noticeably pounded into the head.
Decide what you want first, then work backwards to get there. Oldskool has you covered on most everything. Don't try to outsmart above info ...or overthink the build to get another 10 HP on paper. You won't feel it anyway.
I'm a hobbyist. Not a professional. Don't be hatin'!
"...deck height...I just don't know what to expect in the car and therefore what figure to put into the calculator."
As mentioned, the only way to know your deck height & chamber volume is to measure 'em. I've read that from the factory, the deck height could be .020 or more. Most all Pontiac engines came with the pistons well down in the hole. And, I've also read that many Pontiac heads had larger chambers than advertised.
Also, you never know what specs may have changed, because of previous rebuilds. So, the ONLY way to know is to measure.
My only experience is with 350 heads but the #47s were advertised at 72cc and universally measure 85+/-. At least Pontiac didn't bother to advertise the cc on the #11s which replaced the #47s they simply listed declining compression ratings which told the tale but didn't require specifics. I can't help but think how the engineers who designed the 350 in 1970 must have thought "man it didn't take them long to ruin this thing" Little did they know the smog era was going to make the whole thing a joke soon.
If i'm going to re-bore the cylinders anyway then I will be replacing the pistons which will allow the builder set the deck height correct? I would assume the goal would be 0.00 or as close as you can get.
I had a set of 62's that I believe were said to be 72cc's. They cubed out at 76-78cc's.
...and my rebuilt 400's pistons were down 0.025 in the hole.
"If i'm going to re-bore the cylinders anyway then I will be replacing the pistons which will allow the builder set the deck height correct? I would assume the goal would be 0.00 or as close as you can get"
^Correct re the goal being 0 deck height, all other details being in order. The full sweep enables more efficient cooling. He may have to do some cutting to get at 0. Make sure they use Honing Plates(?) when they bore your cylinders.
It's great you're getting everything done at once. You'll be able to match up everything properly.
I'm a hobbyist. Not a professional. Don't be hatin'!
I'd say the first thing you should know before you take your heads to a machine shop is - Does the machinist know what he/she is doing and has he/she ever worked on a Pontiac? Some think a head is a head but Pontiacs and chebbys are different animals.
You can measure the chamber sizes yourself. Just need a piece of plastic some grease, food colour and a calibrated syringe. You can measure the deck height by cleaning the deck, raising the piston to top dead center and use a deck bridge and dial indicator to measure. If you don't have a deck bridge but a straight edge across the bore and measure from the top of the piston to the straight edge with a feeler gauge, crude but will be fairly close.
You can set your deck height by buying the pistons to match the block, but usually machine the block's deck to match the off the shelf pistons. Most stock replacement or performance replacement pistons have the same distance from the pin to the top.
I agree with the hardened seats, the lead in the old good gas cushioned the valve when it closed in the seat. No cushion now, and, depending on your cam lobe and springs, they can smack in there pretty hard.
Thread in studs don't have a down side, I'd install them. If you're going to have the heads and/or block machined then get straight studs rather than the bottle neck ones and use Poly lock nuts. The stock rocker arms are tightened to 20 foot pounds and that's it, but if the heads and block are machined the bottleneck is no longer at the same height it was when stock, could have an extra 50 thou of preload.
"...If i'm going to re-bore the cylinders anyway then I will be replacing the pistons which will allow the builder set the deck height correct? I would assume the goal would be 0.00 or as close as you can get."
318 Mopar cast pistons are cheaper than 350 Pontiac pistons, and have a .020 larger pin height(compression distance). That puts the piston tops .020 closer to the deck, which will require that less material be machined from the block, to achieve zero deck height. The SP 318 pistons look very similar to the 350 Pontiac pistons. The pins are slightly larger, at .984". But this will only require that the pin holes in the rods will need to be honed to fit the pins. These pistons also come with pin locks, so that you can run floating pins, if you desire.
Well, as usual, Ebay links don't work on this site. But, you can go to Ebay & type in the brand name & part numbers shown. They're about $91 per set. The 285AP pistons have a bore size of 3.910". The 285AP20 pistons have a bore size of 3.930".
There are no cheap forged pistons for the 350 Pontiac. Auto Tec modified shelf pistons, are the cheapest I know of at just over $500. They are lighter, stronger, & can have any size pin & pin location you want.
Don't know your budget. I've read that resizing cast rods + ARP bolts cost $200 +. A rod upgrade is RPM H-beams. They're $400 shipped. They're much lighter, stronger & come in either press-pin or bushed versions for floating pins.
Once again amazing info. I have read that the cast pistons of today are more than adequate for a modified street build 350. And when you look at the price difference it is amazing. But you wonder if you get what you pay for or if the ability to set the pin location ends up offsetting enough machining costs so that you mind as well go for the higher quality pistons?
I keep telling myself that for the millage I will put on this engine/car at this point in it's life this is build will last several generations. Point being do it right and don't cut corners. make the investment. It isn't like the old days where you were thinking that somebody would be doing this again is another 100k or 5 years or whatever. Last year I drove the car barely 100 miles! I go to a local cruise night every other week and a few weekend drives. And in in the northeast the season is short! In a big year I might put 500 miles on.
I haven't really put all the numbers together yet for a budget on this but the more I do the farther away it gets.
Yeah i've read that article before. It's certainly interesting. Of course the 66cc heads and the 9.8:1 compression scare a lot of folks away. However it does speak to the fact that most people are quick to overlook the 350 yet you can follow Pontiac's own lead and get 350hp. And 350hp it very good power in 1st gen Firebird.
Begs a good question. How much horsepower do you really need? That of course is a totally personal question and it varies from car to car but we on this board have established the car. Out 1st generation Firebirds are light. It isn't a Catalina. If you aren't taking your Bird to the track I wonder how often you tap into your HPs? I would wager most folks make big deal about having a lot of horses they paid $$$ for but they seldom use. They baby their cars.
Yeah, a well thought out, correctly built 350, in a correctly set up 1st gen, can be a lot spunkier than an original 400 cube 350hp GTO, especially if that GTO had 3.23 or numerically lower gears.
Not to mention the next 20 years of basically useless cars. Even my 69' grocery getter 2bbl 350 with nothing out back would basically smoke everything that rolled off the line until the late 80s.
I was in high school in the 80s and it seemed like everybody had a late 70s TA. They were pushing 10 years old by then and they were cool and they were cheap! They were NOT fast. It was just gross. Everybody spent every penny they had trying to make their smog 400s beat anything from the 60s. Without a set of heads you were cooked and we didn't have $$ for that. A 69 Firebird or GTO or Chevelle or Camaro would roll up and it would be game over. Stock out of the box.
Yeah, it was GREAT, living thru the Musclecar era of the late '60's & early '70's ! I have very fond memories of watching the parade of Musclecars "makin the loop", in our little country town, and being a part of it.
The cars we had were probably typical of most small country towns of that time period. Small & Big Block Chevys, small and big block Mopars, including a couple of Hemi cars, Mustangs of all sorts, 442 Olds, 400 Birds, 3x2 389 and 400 Ram Air GTO's, as well as one '70 Judge 400/4-speed. I am fortunate enuff to have driven several of the big block Chevelles, a '68 400 4-speed Bird, and having owned a new '69 RA3 4-speed GTO & later, the '70 Judge mentioned.
Still love the cars & most of the music from that period. Love to go to car shows, where I can see some of these old cars & hear the old music.
Speakin of car shows, a good Pontiac friend just won "best of show", with his '69 4-speed Bird, at the show he attended. And it ain't no trailer queen. He drives it the the shows & cruise-ins. North of 455 cubes, alum heads, and a solid roller cam. Full 3" pipes out the back. He won lots of dirt track races & a few season championships, with Pontiac power. Also worked at a Pontiac dealership back in the old days.
No to mention I'll bet there was some good eatin' chichin'!!! Sweet car. Being a little younger the hot cars of my youth were 5.0 mustangs and IROC Z28s. Turbo TAs. But when the old muscle rolled up everybody gathered around!! When I first went to my now wife's house and I walked into the garage and her old man had a 69 Firebird sitting there I almost dropped!! Now it sits in my garage!! Can't wait to bring it back and more.