[SD455DJ]

This is my brother's numbers matching original 56,000 mile '69 350HO/M20/3.55 rear Firebird with mostly original paint at the 2019 TA Nat's. It came with the Décor option and has it's original full size wheel covers (not on in this picture). The original engine (w/ 48 heads) was rebuilt by the previous owner and is very strong. It has an actual 9.5 compression and 067-ish cam in it (204/214/112) very similar to the Summit 2800. The butt-o-meter says mid-13's and it drives so nice...gets 18-19 mpg too!

Dennis

[rdl]

Originally Posted by SD455DJ

The butt-o-meter says mid-13's and it drives so nice...gets 18-19 mpg too!

Really nice looking example; thanks for posting. I’d be dubious on the performance AND mileage claims as both being accurate together on the same car. What is the car’s typical range on the highway on a tank of fuel? I would expect ~200 miles or so with that combination.

[SD455DJ]

Originally Posted by rdl

Really nice looking example; thanks for posting. I’d be dubious on the performance AND mileage claims as both being accurate together on the same car. What is the car’s typical range on the highway on a tank of fuel? I would expect ~200 miles or so with that combination.

Rob (rdl) – These are actual numbers. The mpg’s were determined on the 600 mile round trip journey to the 2019 TA Nationals and back with Dan calculating at each fill up. This was roughly 90% country road steady state driving at 55-65 mph mixed in with a dozen, or so, small town stop & go. I was able to manage 14-15 mpg in my ’71 455HO Formula with 3.42 gears. It doesn’t surprise me that a smaller cube engine (100+ c.i.) with higher compression (9.5 vs 8.4) along with 400 lbs less weight to tug around (1st gen vs. 2nd gen w/AC) with a deeper 1st gear and slightly higher rear end ratio for (8.95 vs. 7.52 1st gear multiplication for a 20% advantage) could get 4-5 mpg more.

From the performance perspective, the previous owner to Dan brought the just-purchased all original (50k miles) Firebird up to the Pure Stock Drags (2011) and managed to a run 14.38 at 98.66 mph with the original 3.55 open rear end on new repop Firestone F70-14’s on 14x7 Rally II’s…pretty good I’d say.

Before the next race (2012) he had rebuilt the engine (stock bottom end with .030 forged pistons) with a pretty big CC cam (XE268: 224/230/110 @ .477”/.480”)…way too big for the 350. It pushed to power band higher than it was designed to rev with no low end torque. The compression wasn’t maxed out and Whistled at 9.5 to 1 warm. The pistons may have a small dish, but haven’t verified. An Eaton posi unit was added and a better 2.5” exhaust system (Flowmaster) was added. With all the changes it ran 13.97 at 100.25 mph (3658 lbs. w/driver) with the poorly chosen cam. Tom Miller ran a 13.63 @ 102.58 in his ’69 Carousel Red 350HO Firebird with a TH400 and 3.73 gears (3576 lbs) back in 2006 (don’t know the engine specs).

When Dan bought the car a couple years later, he hated driving it with the CC cam that was in it from the rebuild. Dan worked on the DeskTop Dyno and designed a custom cam that is in between the 067 & 068 cam specs with .425” lift. He designed it for maximum torque yet good hp, like Mac McKeller did. It’s in the 206/218/113 range. The smaller cam made a huge difference with how the car drives and makes its power in the low and mid-range now and revs to 5500 rpm easily. Tom Miller drove the car this summer and said it felt faster than his old ‘69 350HO Bird. It has to be proven on the track someday, but Dan and Tom have enough seat time to make fairly accurate predictions.

This is not meant to be an argument, but clarifications. I can honestly say we have all been impressed with the performance potential of the Pontiac 350HO’s and shouldn’t be overlooked. They run just as well with the small valve heads.

Sorry about the long read.

Dennis

[rdl]

Hey Dennis, hope you’re keeping well. Thanks for the reply and no need to apologize for the detail. As you probably know I’ve made the drive from Toronto to the PSD and then raced ‘Iron Man’ as well. My honest blueprinted combination averages about 200 miles to a tank of fuel (Dan has my car spec’s). That equates to about 11 mpg cruising around 60 - 65 mph. I’m not arguing with your claims (the 350HO is a cool package) it just seems incongruent with my own driving experience. Maybe it’s the Canadian gas!? lol

[wovenweb]

Originally Posted by SD455DJ

Tom Miller ran a 13.63 @ 102.58 in his ’69 Carousel Red 350HO Firebird with a TH400 and 3.73 gears (3576 lbs) back in 2006 (don’t know the engine specs).

Did Mr. Miller later drive a '69 Buick with a 350? If so, he had pretty good times with it also.

[Ponchy]

Originally Posted by ponyakr

"...Not sure which heads the 68 350-HO came with..."

#18

http://www.wallaceracing.com/enginesearch4.htm


This really has almost nothing to do with this thread. But, since I'm a drag racer, when I hear about a '68 350HO, I now automatically think of Adam Strang's '68 Bird Stocker. He tried a 350HO in it & ran some 10.80's, IIRC. Did I mention that this has almost nothing to do with this thread ?

There is some YT video of a guy racing a very nice '69 Custom S with 350 HO and he smoked just about everyone he came up against...usually, others had larger engines, too.
Giant Killer.

[SD455DJ]

Originally Posted by rdl

Hey Dennis, hope you’re keeping well. Thanks for the reply and no need to apologize for the detail. As you probably know I’ve made the drive from Toronto to the PSD and then raced ‘Iron Man’ as well. My honest blueprinted combination averages about 200 miles to a tank of fuel (Dan has my car spec’s). That equates to about 11 mpg cruising around 60 - 65 mph. I’m not arguing with your claims (the 350HO is a cool package) it just seems incongruent with my own driving experience. Maybe it’s the Canadian gas!? lol

Hi Rob...we're all doing well. I wish all you north of the border guys could make it this year to the race. Dan's got the carb on the 350HO pretty well sorted out and it's an econo-cruiser with the higher compression and cam. I recall it made it all the way down to Dayton from his home on one tank. I, on the other hand, had to stop after 225 miles to fill up.

Stay Safe!

Dennis

[SD455DJ]

Originally Posted by wovenweb

Did Mr. Miller later drive a '69 Buick with a 350? If so, he had pretty good times with it also.

Wovenweb - Yes, back in 2016 Tom brought a great stripper Buick Special 2-dr coupe with the 280 hp 350, TH350 and 4.11 gears and it went 13.16 (!) at 103+ mph (!!) and weighed only 3525 lbs with Tom (!!!). That 350B was maxxed out to the extent of the rules...obviously. It is a very cool car.

Dennis

[SD455DJ]

Originally Posted by Ponchy

There is some YT video of a guy racing a very nice '69 Custom S with 350 HO and he smoked just about everyone he came up against...usually, others had larger engines, too.
Giant Killer.

Ponchy - If it is a red with Black top Tempest Custom 2-dr Hdtp, that would be Jeff Sawruk. He gave the 340 Dusters and W-31 Old's fits.

Dennis

[Ponchy]

That would be the one!
Apparently, laid waste on a few big blocks, too....like this 440 Roadrunner!

https://www.youtube.com/watch?v=O-pT4E-WziM

...love it when the "underdog" takes it to a pentastar product.

[SD455DJ]

I need to make a few corrections...the milder cam that Dan installed is actually 203/216/112 @ .422"/.438" lift, so a little milder. The cam that he removed is a Crane H-278-2 (222/234/114 @ .467"/.494" lift), which is a good cam for a 10.0 400 with big valve heads and RA manifolds. The replacement exhaust system is a Pypes crossflow w/X pipe system with the 2.5" headpipes.

The 48 heads combustion chambers measured in at 66.7 cc's average. He didn't find any marks or stampings to distinguish this head from the bigger chamber 48's used on 400's.

The pistons are .030" in the hole (!) and uses .040" Cometic head gaskets (.070" quench!!...not ideal). The block is still standard bore (3.876") and has Silvolite cast pistons, not forged as I thought. Dan would have done many things different on this numbers matching 350 if he rebuilt it, but it does run good. The static compression calculates out to 9.45. If it was zero decked, it would be close to 10.0 to 1.

Dennis

[johnta1]

Dennis, did you ever race at St. Louis in the late 80's possibly early 90's in a 'Stock' type race? (can't remember what they called it)
I raced there and there were not many Pontiacs. Got down to 10 cars (they paid to 8 )

A friend went there with a 71 TA, can't remember how he did, went a few rounds.

[Ponchy]

Originally Posted by SD455DJ

I need to make a few corrections...the milder cam that Dan installed is actually 203/216/112 @ .422"/.438" lift, so a little milder. The cam that he removed is a Crane H-278-2 (222/234/114 @ .467"/.494" lift), which is a good cam for a 10.0 400 with big valve heads and RA manifolds. The replacement exhaust system is a Pypes crossflow w/X pipe system with the 2.5" headpipes.

The 48 heads combustion chambers measured in at 66.7 cc's average. He didn't find any marks or stampings to distinguish this head from the bigger chamber 48's used on 400's.

The pistons are .030" in the hole (!) and uses .040" Cometic head gaskets (.070" quench!!...not ideal). The block is still standard bore (3.876") and has Silvolite cast pistons, not forged as I thought. Dan would have done many things different on this numbers matching 350 if he rebuilt it, but it does run good. The static compression calculates out to 9.45. If it was zero decked, it would be close to 10.0 to 1.

Dennis

I'm liking the numbers on that milder cam.
Camshaft make and model please?

Ponchy

[SD455DJ]

Originally Posted by johnta1

Dennis, did you ever race at St. Louis in the late 80's possibly early 90's in a 'Stock' type race? (can't remember what they called it)
I raced there and there were not many Pontiacs. Got down to 10 cars (they paid to 8 )

A friend went there with a 71 TA, can't remember how he did, went a few rounds.

John, I didn't go and not sure if Dan did...was there a '71 455HO T-37 there? You wouldn't have missed it if it was. He thought the series of races was called the Musclecar Nationals and was held at various tracks across the country. He and a local friend were hired and flown to several racetracks to do the tech. I'm not sure if St. Louis was one of those, but he wasn't racing at the events he teched at.

Dennis

[SD455DJ]

Originally Posted by Ponchy

I'm liking the numbers on that milder cam.
Camshaft make and model please?

Ponchy

Ponchy - Dan had the cam custom ground by Comp Cams back in 2013. He said he would just use the Summit 2800 cam as it is essentially the same specs (204/214/112 @ .422"/.444" vs. 203/216/112 @ .422"/.438")and save some money.

Dennis

[unruhjonny]

I am surprised no one mentioned this sooner:

Originally Posted by thews

... The 69 and 70 D port "RAIII" heads are the same 72cc D port heads. #62, #48, #12 and #13 are the exact same head. Outside of the stamped numbers, they are all put on 350HP engines. Does anyone disagree that those 4 head numbers are different in any way?

all four castings (over two model years) have nominal cc ratings of 72cc;
all four castings were used in engines that had the same (or similar) horsepower ratings.

I believe that of late, there have been some corrections in this matter, so I am typing this in hopes of helping to set things straight:

1969 #62 heads = 77cc (aprox)
1970 #13 heads = 77cc (aprox)
1969 #48 heads = 67cc (aprox)
1970 #12 heads = 67cc (aprox)

1969 'L78' 400-4bbl 350hp WX/XH/YS/YT = #62 heads
1969 'L78' 400-4bbl 350hp WT = #48 heads
1970 'L78' 400-4bbl 350hp WX/XH/YS = #13 heads
1970 'L78' 400-4bbl 350hp WT = #12 heads

All L78 engines for these years used 'regular' 750cfm carbs with pull over enrichment airhorns, standard cast iron four barrel intake manifolds, and standard "log" exhaust manifolds.
For both years, these engines when installed in Firebirds carried a 330hp rating.
All these engines used 067, with just two exceptions:
1) XH engines installed in full sized cars with automatics used a 066 cam.
2) early(?) 1969 WT engines used a 068 cam.
For both of these years, the Tempest/Lemans/Firebird when equipped with this engine and a manual transmission, were the 'hot ticket' because they used the higher compression "Ram Air III" heads.

I used to go along with the assertion that supposedly some automatic RAIII engines were purported to have 62/13 heads, but I am incline these days to believe that was bunk.

Originally Posted by SD455DJ

... This is not meant to be an argument, but clarifications. I can honestly say we have all been impressed with the performance potential of the Pontiac 350HO’s and shouldn’t be overlooked. They run just as well with the small valve heads.

It has been my belief for quite some time that these cars have been quite overlooked.
Even the 75-77 L76 350-4bbl engines seem overlooked, when they are better than I'd wager many people think they are.

I just looked for the picture that I could swear I remember taking, but couldn't find it;
I believe it was at the 2018 Portland Swap meet, that someone (in the far east building) was selling a whole (taken apart, less carb) 1968 Pontiac 350HO;
Since I like these, it piqued my interest, especially since no one seems to pay them any attention or ever offer them for sale.

[Ponchy]

Originally Posted by SD455DJ

Ponchy - Dan had the cam custom ground by Comp Cams back in 2013. He said he would just use the Summit 2800 cam as it is essentially the same specs (204/214/112 @ .422"/.444" vs. 203/216/112 @ .422"/.438")and save some money.

Dennis

....hmmm....I wasn't aware of the summit cam.
Thank you very much for that info.

Ponchy

[trishieldchief]

The first car I bought at age 16 was a 1967 Firebird 326 HO HD 3 speed on the floor with standard 3.36 open axle.

Loved that car, in stock form it was a real ripper.

[johnta1]

He thought the series of races was called the Musclecar Nationals

That was it!



Don't think I remember that car, I remember there was an AMC (AMX maybe?) that went a lot of rounds. (about the only one there I think)

[thews]

Originally Posted by unruhjonny

I am surprised no one mentioned this sooner:


all four castings (over two model years) have nominal cc ratings of 72cc;
all four castings were used in engines that had the same (or similar) horsepower ratings.

I believe that of late, there have been some corrections in this matter, so I am typing this in hopes of helping to set things straight:

1969 #62 heads = 77cc (aprox)
1970 #13 heads = 77cc (aprox)
1969 #48 heads = 67cc (aprox)
1970 #12 heads = 67cc (aprox)

1969 'L78' 400-4bbl 350hp WX/XH/YS/YT = #62 heads
1969 'L78' 400-4bbl 350hp WT = #48 heads
1970 'L78' 400-4bbl 350hp WX/XH/YS = #13 heads
1970 'L78' 400-4bbl 350hp WT = #12 heads

All L78 engines for these years used 'regular' 750cfm carbs with pull over enrichment airhorns, standard cast iron four barrel intake manifolds, and standard "log" exhaust manifolds.
For both years, these engines when installed in Firebirds carried a 330hp rating.
All these engines used 067, with just two exceptions:
1) XH engines installed in full sized cars with automatics used a 066 cam.
2) early(?) 1969 WT engines used a 068 cam.
For both of these years, the Tempest/Lemans/Firebird when equipped with this engine and a manual transmission, were the 'hot ticket' because they used the higher compression "Ram Air III" heads.

I used to go along with the assertion that supposedly some automatic RAIII engines were purported to have 62/13 heads, but I am incline these days to believe that was bunk.



It has been my belief for quite some time that these cars have been quite overlooked.
Even the 75-77 L76 350-4bbl engines seem overlooked, when they are better than I'd wager many people think they are.

I just looked for the picture that I could swear I remember taking, but couldn't find it;
I believe it was at the 2018 Portland Swap meet, that someone (in the far east building) was selling a whole (taken apart, less carb) 1968 Pontiac 350HO;
Since I like these, it piqued my interest, especially since no one seems to pay them any attention or ever offer them for sale.

Thanks for this. I'm currently pulling all my hoarding stuff out of storage and plan on CCing the heads I have. I have a stock 69 350HO engine complete with #48's, I believe two standard sets of #48 and one set of #62, so I can add some data when I pull them all out I'll update this thread.