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303/366 specs

  
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303/366 specs

 
RumRunner1 RumRunner1
Enthusiast | Posts: 580 | Joined: 12/10
Posted: 11/10/12
04:20 PM

Cool Hey tribe! i need some specs for a collegue that wants,and I mean, "WANTS" to duplicate the 366 Pontiac engine for a road racing auto crossing weekend warrior in a first gen firebird.. Grin I am not kidding.... he is putting his C-5 vette up for sale and gonna dump some big bucks into this project.. I have read the article in h.p.p interviewing Herb Adams and co. and as awesome as the article was, the 303/366 was referenced as a "short deck Pontiac". WELL,,,,,how short chief????? what was the deck height???? would all of our wonderful afermarket alum, heads and stuff bolt up? I haven't called "all-Pontiac" or J.Butler and co. to ask if a customer can order a "short deck" option on the aftermarket block until I get the 303/366 specs.(but that would be freaking awesome) this guy is Dead serious wants to start now,and will NEVER put a sbc or ls-xxx motor in it.. now before someone critiques this plan. my collegue will put fuel injection on it, and possibly a turbo or centrifigal blower.he is well experienced and educated and the appeal of the 366 is too much for him to let go,, the firebird will be "race-spec" according to certain rules and live in the high rpm world... thank you.. also engine gurus are welcome to suggest a possible de-stroke idea, with custom stuff. thank you.. Grin  
Widetrack,Superduty,Ram-Air.The chief will never die!

ROWSLEY ROWSLEY
Guru | Posts: 1015 | Joined: 07/11
Posted: 11/12/12
12:44 AM

i found some info on the trans am 303 short deck. bore 4.125 stroke 2.84 the deck was cut down 1 1/8", 2.5" main dia,7.08 rod, 430 hp with tunnel port heads,480 hp with ram air 4 heads, 8000 red line.

the s.c.c.a disallowed the 303 after 1970 but did allow destroking of production engines.

the 366 short deck was for nascar later run in s.c.c.a. 4.150 bore, stroke 3.375, rod center to center 6.08 525 hp. that is all i can find so far. the 366 was the begining of the SD455.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

RumRunner1 RumRunner1
Enthusiast | Posts: 580 | Joined: 12/10
Posted: 11/12/12
11:40 AM

Thanks a bunch Rowz"!!!! Yeah I got the same rotating assembly specs.. but, the deck height reduction was great info!!!! where may i ask did you find the info on the 1 1/8" cut? as far as the article i read,, herb adams went to the pontiac foundary and either machined it or had a cast made with a short deck..thats the question for the 366..the 366 built for the Nascar grand am and later in the "appliance wheels" silverird 78 trans am for scca is what my buddy is after. and if it was a 4 bolt main 400 base block how much decking was conducted?? I wonder if we could deck down a 400?? and build it to spec!! he doesn't have any problem using a sheetmetal intake made to mate to the loss of standard deck height.. whay all the buzz??? to make a screaming pontiac engine linked to yesteryear and for freaking bragging rights that's why.. yeeeehaaaw!!!! any help before i track down herb adams or call Mr. demauro from H.p.p. and heck, why not go exotic once in a while thats what Mr. herb did right????  
Widetrack,Superduty,Ram-Air.The chief will never die!

Pontiacman8 Pontiacman8
Moderator | Posts: 5775 | Joined: 02/08
Posted: 11/12/12
02:26 PM

http://www.wallaceracing.com/RAV-articles.html  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

ROWSLEY ROWSLEY
Guru | Posts: 1015 | Joined: 07/11
Posted: 11/13/12
01:09 AM

PONTIAC MUSCLECAR PERFORMANCE BY  PETE McCARTHY & JOHN ANGELES

NOT SURE ON THE DECK HEIGHT OF THE 366 SEEN REFERANCES TO BOTH SHORT & TALL. SAME FOR THE 6.08 & 7.08 ROD LENGHT.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

RumRunner1 RumRunner1
Enthusiast | Posts: 580 | Joined: 12/10
Posted: 11/13/12
11:25 AM

P-man thanks buddy..(good to hear from you) i read the Wallace article, and i was like "duh" the ram air five and evolution of the super duty 455 program, very detailed article from the eighties! my light bulb should have came on,,, thanks again. rowz i will check it out...thanx brother, it just seems conflicting from author to author about a short deck Pontiac or a true small block "Ponch" engine.. obviously the 303 being a "as cast" short deck we know.. but it gets kinda hazy when the 366 comes into the conversation, i am hoping the 366 was a re-enforced cast 400, meaning the main bearing size was the same, deck height etc... basically my associate would like to find a nice 400 core and de-stroke/bore and copy the b/s r/s of the 366. except with "premo" parts of today. (*you get the idea,) He is also considering the CV-1 heads as well,..I'm gonna do some diggin on this one,,I' will keep you posted, and feel free to drop a reply any time for an update it would be most appreciated  
Widetrack,Superduty,Ram-Air.The chief will never die!

ROWSLEY ROWSLEY
Guru | Posts: 1015 | Joined: 07/11
Posted: 11/13/12
12:23 PM

my book says the 366 block is the same design as the sd455 block. if you destroke a 400 you will need to turn it above 6500 to make good power. high rpm motors don't last long! you might look at boring or stroking a 350(354) and keepin the rpms down.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

RumRunner1 RumRunner1
Enthusiast | Posts: 580 | Joined: 12/10
Posted: 11/14/12
11:05 AM

I have found the info i need, and thanks again fellas for all the input. yes, I agree the high rev's take their toll on engines, however, with all the modern forgings,lubricants,bearings,dry sump and such. I don't see anything wrong with a few blips coming outta the straight away at 7,000. I showed my buddy the video of roger bolliger's 70" trans am with a butler built big inch poncho and he was ready to go to Nurburgring! and if that bad boy can do it with a full on race car I think we can have some fun with a dual purpose short track road racer/autocross weekend warrior..thanks guys I will provide an updates as they come thanks again  
Widetrack,Superduty,Ram-Air.The chief will never die!

RockyRotella RockyRotella
New User | Posts: 46 | Joined: 08/07
Posted: 11/14/12
07:28 PM

Just wanted to clarify some contradicting information about the 303 and 366. I recently spoke to Herb Adams and the late-Jeff Young about this very topic.

The 303 was developed as a tall-deck (meaning normal deck height) engine with tunnel port heads. At some point the tunnel heads were replaced by modified RA-IV units, which proved a better match for the small-cube motor. The short deck variant was developed strictly for SCCA racing and it was a direct attempt at shedding weight from the engine. Only 25 were made and all were used in SCCA competition. There were also tall deck 303s floating around at the same time.

The 366 was a direct attempt at making a high performance NASCAR engine. A short-deck variant was proposed, but the 366 was only a tall deck engine when produced.

The SD-455 was developed when Pontiac decided to build a high performance street engine and it was an evolution of the 366.  

RockyRotella RockyRotella
New User | Posts: 46 | Joined: 08/07
Posted: 11/14/12
07:33 PM

One last tidbit of info. The 303 and Pontiac's late-70s 301 essentially share the same deck dimensions. It would take some work, but you may be able to use a 301 block (301T turbo block is beefier) as the basis of your build.  

RumRunner1 RumRunner1
Enthusiast | Posts: 580 | Joined: 12/10
Posted: 11/15/12
12:06 PM

Thank you Mr.Rotella. I appreciate the overview, and the clarification of the subject as to "respectfully" dismiss any speculation from numerous articles and second hand info, I spoke to Mr. Pete McCarthy the other day and he has a detailed publication on the subject (as provided by P-man) and commented on the "standard and short deck version as you stated.. I plan to acuire this "pub" as it has a very detailed outline on the subject. Of course, your source (Herb Adams) is the final say, period..The 301-T block is tempting, and I and my associate will "mull that over" Thank you.. also to my fellow forum members thank you once again for your input and time to disclose and/or provide leads and information, this is a venture worth pursuing IMO.. i will keep you posted.  
Widetrack,Superduty,Ram-Air.The chief will never die!

RockyRotella RockyRotella
New User | Posts: 46 | Joined: 08/07
Posted: 11/22/12
08:57 AM

Glad to help out!

You spoke to Pete recently? How's he doing?

I've been trying to reach him, but he hasn't replied to emails and his cell phone is always off. How did you reach him?  

ROWSLEY ROWSLEY
Guru | Posts: 1015 | Joined: 07/11
Posted: 11/24/12
12:41 AM

rocky  don bennett told me to tell you and your dad hi. he said you guys are doin up a bitchin superduty trans am.

would be nice if you all could come to the pontiac cruise in next june. it will be on sunday the 2nd.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

RockyRotella RockyRotella
New User | Posts: 46 | Joined: 08/07
Posted: 11/25/12
06:20 PM

Thanks for the message! Tell Don hello for us and that we're doing well. We've often talked about going to Don's cruise, but haven't made it yet. That's something we really need to consider.