I didn't think of this earlier, but is the Poncho 400 engine physically taller than the Chevy 400? I've already planned on a new hood which adds an additional 1 1/2"-2" clearance. Will I be ok with this? I'll be running the Q-Jet 750 carb with the drop base dual snorkel and a taller lid allowing a 3" element.

------------------
DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 LO3

 

They are just a little taller. How much depends on the intake manifold. They are alot wider, which is where you will have the most clearance problems.

 

Yes, the pontiac is a BB, the chevy is a SB.

Here's another thought. If you were thinking chevy 400, you will have trouble w/ the transmission (bolt pattern). You probably already figured that out though.

Clayton

 

Ok, that's what I figured on the height. I should (hopefully) be alright with what's planned. I'm aware of the Poncho's trans bolt pattern.
*the Chevy 400 trans bolt pattern is different?

------------------
DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 LO3

 

Its taller, but keep in mind they stuck those under the hoods of 1st and 2nd gens with plenty of clearance.

And there is no Pontiac BB, or SB for that matter.

 

Ok, now i'm thrown...I know the Pontiac blocks weren't BB or SB, but for comparison, what's the Poncho 400 physically closest to, in Chevy terms?



------------------
DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 LO3

 

Its inbetween the BB and the SB.


Closer to the BB side though. I always correct people that say the Pontiac is a big block engine, because it isnt. You need to have a small block first, and thats something they dont have.

 

The Pontiac 400 is closest to a BBC in size comparison. What he meant by there was no such thing as SB and BB Pontiacs is that all Pontiac V8's from 265 - 455 cu in were physically the same size. The 301 had a little shorter deck height, and different oil filter that stuck out horizontally as opposed to the Vertical (like Chevys) style that all other Pontiac V8's used. They also had a unique head (casting # 01) that used 1 intake port per 2 cylinders meaning each head had only 2 intakes ports. They were about the equivelent to a Chevy swirl-port head as far as performance goes which mean they sucked. I've built several Pontiac engines myself and they are Torque Monsters!! I have a 69 350 HO in my 69 Firebird, a '68 Ram Air III 400, and a 66 389 4V. I built a 72 400 w/ 68 #13 heads for a friend's 78 T/A, and its a mild 9.5:1 street engine w/ a small hyd cam, dual plane intake, a small 2500 convertor and 3.42 gears and it still knocks down 12.80 - 12.90
at 105 - 106 mph. Not bad considering he drives the car almost daily and it weighs in at a tubby 3820# with him in it. I've listed a few sites below that deal strictly w/ Ponchos, check them out. I have dealt with all of them and they are pretty nice ppl to deal with. I have used Jim Butler more than anyone, and those guys know their s**t when it comes to Pontiacs. I'd like to see a "true" Poncho in a 3rd Gen. Keep us posted.

Jim Butler Performance
http://www.jbp-pontiac.com/


Rock And Roll Engineering
http://www.pontiacengines.com/

Wenzler Pontiac Performance Parts
http://www.execpc.com/~lewenz/


------------------
82 Z28 383, Ported 215cc Dart Iron Eagle Heads, Comp custom grind roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 800 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET: *NEW ENGINE* untried at track!!


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock
New Best ET: 14.91 @92.9
Bassett Racing
Mid Atlantic F Body -82 Z28 Page

R.I.P. Dale Earnhardt #3

 

Thanks guys, i'm feeling more confident about this with every reply. All's I want's to do is build a unique N/A car that will run with the GN's and LT1's/LS1's. Looks like i'm on my way!

------------------
DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 L03

 

Why not go with a 455, or a stroked 400? There is no replacement for displacement.

 

I second that. Jim Butler and RRE sell cranks that will stroke a 400 up to a 455. The factory Bore and Stroke configuration on a 400 is a 4.121 bore and a 3.75 stroke. The 455 is 4.151 X 4.21 The mains on the 400 are 3" while the 455 has 3.25" mains. To stroke the 400 to a 455 all you have to do is have the block bored .030" (which it probably needs anyway) and buy a 455 crank that has been turned to 3" mains. They used to cost $335 at Jim Butler Performance, but I haven't checked in a while. There is no clearancing and you can use the 400 rods and new STD bore 455 pistons. But if that is out of your means,a properly specced 400 will easily wear all the LT1's and LSI's you want. Just try to get some of the better Pontiac heads such as #16, #48, #13 or if you get REALLY lucky, find some of the RA IV heads.

------------------
82 Z28 383, Ported 215cc Dart Iron Eagle Heads, Comp custom grind roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 800 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET: *NEW ENGINE* untried at track!!


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock
New Best ET: 14.91 @92.9
Bassett Racing
Mid Atlantic F Body -82 Z28 Page

R.I.P. Dale Earnhardt #3

 

Stroking the 400 is pretty much what I had in mind.

------------------
DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 L03

 

Edelbrock makes aluminum heads that are really the best way to go on a Pontiac. They are not cheap at $1600 a pair ready to bolt on, but they are the best.

 

Great thread. I've been lurking, watching for a while and finally got around to registering here. I just picked up a 428 poncho from a 68 GP with the intention of finding a 3rd gen bird to drop it in. I'll need to double check but I "think" it has the #62 heads. What kind of clearance issues are you going to have with the inner fenders and shock towers if any? Good luck.

------------------
1990 6speed Corvette
SLP SS 1 5/8" LT-1 headers(modified to fit L-98), true duals no cats, no mufflers(just resonator tips), smog pump elim kit, !cags, Accel Base, Ported plenum and all the free stuff.
Best 1/8th mile time 8.67 at 82.3mph.
Previous cars: 69 Firebird 400, 86 Firebird 2.8, 94 Trans Am, 95 Trans Am.

 

Your engine most likely has the #62 heads, because #62's did come on 68-69 428's. It could be either a 375HP or 390HP factory rated engine. It has the large crank journals (3.25") like the 455. It has a 4.121" bore (same as the 400) but has a 4.00" stroke. These are great engines for a buildup. In the late 60's, there was a Pontiac dealership called Myrtle Motors that outfitted Hi-Po Pontiac Firebirds to compete with the Baldwin-Motion and Yenko 427 Camaros. The engine they used was the 428, and even though it is not widely known, the Myrtle Motors Firebirds were as fast as and in some cases faster than the Yenkos/Motion Camaros. The ones that Mytrle Motors built were dealer-built super cars and they were 11 second factory "race cars" if you will. The #62 heads you have ,as far as factory D port heads go, are some of the best. They have 2.11" int, 1.77exh tuliped valves and have 72 cc combustion chambers. They also come factory with screw in studs and guide plates. Also, every 428 block I've ever seen was a 4 bolt main, and came factory with forged pistons and a windage tray. Check out the Jim Butler and RRE links above. There are several ported cast iron factory D port headed Ponchos that they have built that run in 8's and 9's in 1/4. Sure, Edelbrock aluminum heads are great, but there is a ton of potential in the factory Hi Po heads such as your's, even unported. Now, as far as clearance goes, I can't help because I have never put a Poncho in a 3rd Gen. I would think that you could get chassis engine mounts from an older Firebird, since they were basically the same as the older Camaros, and you would need either an adapter plate for a Chevy tranny or use a BOP or "corporate" dual pattern case. Check out Wallace Racing http://www.wallaceracing.com/index.htm , they have a head and block decoder for Pontiac engines and a lot of other Pontiac Only related info.

------------------
82 Z28 383, Ported 215cc Dart Iron Eagle Heads, Comp custom grind roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 800 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET: *NEW ENGINE* untried at track!!


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock
New Best ET: 14.91 @92.9
Bassett Racing
Mid Atlantic F Body -82 Z28 Page

R.I.P. Dale Earnhardt #3

[This message has been edited by Basett Racing (edited May 21, 2001).]

 

I'm just starting to plan my engine, which will be pontiac based, just a couple fast general quesitons....

Is there any advantage to stroking a 400 to 455 over just started with a 455? My orinal plan was to go 400 in the 86 and save teh 455 for an earlier model car, you know just to add diveristy in the collection.

What are the options with fuel injection? I would prefer a miniram style induction rather than a throttle body for the performance and hood clearance. Is it possible to drill the edelbrock heads for a miniram intake?

Cost is not a factor here, everything is going to be the best and done right.

------------------
1986 Trans Am
305 TPI
"If it's not one thing, it's another!"
http://www2.hanover.edu/hierlmeier

 

As far as factory heads, if you want to run on pump gas, get some 6X castings. They have larger chambers and hardened valve seats. The older 16, 62, 670, and many others, give around 11.5/1 compression on a 455. Race gas only territory. The 6X heads are common 70s smog heads, and an easy and cheap score at a junkyard. Go to www.gtoheaven.com for Poncho tech.