I initially wanted 3.08's too when the plan was sticking with a TH400. Since I want to take this car on the road I'm really leaning towards the OD instead. I'm REALLY trying to convince myself that a 7.5" rear end will be fine but I know I'm not going to baby the 455 when it's done. Who builds for 550+ ft lbs of torque and babies it?
78 Grand Prix project
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OD makes the most sense if you're planning on long hauls. It wasn't that important to me, I'm sort of a dinosaur anyway, so I just stuck with the TH350 that came with the motor. And yeah, the 7.5 will work for some guys who can't afford 8.5s or aren't building anything that big, but when you're putting the attention to detail into a car like yours, with a motor like that, you kind of have to go 8.5. For me, the 3.42 posi is costing me less than building my 7.5 into a 3.08 posi, so the money saved will just go towards 255s instead of 235s, and I'll drive 5 MPH slower and be at the same RPM.
Intragration said:
I've been wanting to do a Rt. 66 tour, the CC Summer Nats, Power tour, etc for the last 10 years or so. I've had a lot of block burner type cars and I really want something roadworthy this time around.
GbodyVet you are going to love that combination. Its similar to mine and I absolutely loved driving that car. I have a buddy with a 9.40s 66 Chevelle. Says hes had more fun riding in my car then ever did his own because it sits most of the time. He pretty much has to trailer it anywhere and he can't really afford to run it often or break it. The throttle response & grunt in the rpm where you drive it even in OD kept you grinning.
As we have talked before I used a well built 200-4R with billet forward drum and a 2,800 stall lock up converter. Before the 442 I had it in an 88 Cutty with 28 tall tires, 3.42 8.5, Qjet, 230@50 cam and 10-1 static compression. The converter drove like a regular car and locked up at cruise even below 2,800 for the least rpm and best mpg. It also doesn't put a load on the cooling system like a regular high stall convert does. The only time you knew you had a stall is when you smacked the throttle to come out of the hole hard or kicked it down a gear. It pulled off 17.0 hwy on an interstate trip running 72-75 mph turning 2,400 to 2,600 which was right where the cam was efficient and the throttle opening was light.
As we have talked before I used a well built 200-4R with billet forward drum and a 2,800 stall lock up converter. Before the 442 I had it in an 88 Cutty with 28 tall tires, 3.42 8.5, Qjet, 230@50 cam and 10-1 static compression. The converter drove like a regular car and locked up at cruise even below 2,800 for the least rpm and best mpg. It also doesn't put a load on the cooling system like a regular high stall convert does. The only time you knew you had a stall is when you smacked the throttle to come out of the hole hard or kicked it down a gear. It pulled off 17.0 hwy on an interstate trip running 72-75 mph turning 2,400 to 2,600 which was right where the cam was efficient and the throttle opening was light.
dogshit said:
I've seen both ends of the spectrum with low gears & 3 speeds vs 4 speeds. I must say the OD makes a much more enjoyable driver. The beauty of it is that big cube engines make a ton of torque under 3k rpms and that's where a street driven car spends most of it's time.
Here's a quote from a Car Craft article that got me interested in building a 455. http://www.carcraft.com/techarticles/11 ... index.html
I have that issue. 8) In fact I had that whole series and they expanded and did one on the 454, Ford 460, & Chrysler 440 and then a final that had a comparison. All built as comparable as could be. The Olds did the poorest but it had a little bit of a disadvantage in being first and using a little less compression than the rest. The Buick 455 won but it also cost the most. Steve Brule did all the dyno sessions on the same dyno. The only one they missed was the Cadillac 500. A vendor has the same build Cad 500 crate motor that makes 500 HP & 600 TQ. My own 509 build used slightly less compression & cam. Without dyno tuning calculated from actual race weight and trap speeds made 450 HP & 570 TQ. The Caddy has an extra 45 cubes and a longer stroke which brings the power band down in rpms a little lower than a comparable cam & compression Pontiac. 
I am not saying its a better motor just a little more torque and comes on a little sooner. Even at 1,500 to 1,800 in overdrive it did not seem to lug on the interstate on southern Ohio rolling hills. But mine seem to require a little more throttle opening than say at 2,200 to 2,600. Lot of little variables come in to play here what timing a particular motor likes, carb settings, gear, tire height, the cam and how it was installed advanced or retarded.
I got in more little street skirmishes with this car than the GN because it didn't sound wild and even the 442 looked like chicken to every Mustang & Camaro. It looked stockish so they would just assume it was 307 powered.
In the GN they will give you a thumbs up and only rev at you if they are armed with a butt load of spray. In the Cutty they rev at you and grin.
I am not saying its a better motor just a little more torque and comes on a little sooner. Even at 1,500 to 1,800 in overdrive it did not seem to lug on the interstate on southern Ohio rolling hills. But mine seem to require a little more throttle opening than say at 2,200 to 2,600. Lot of little variables come in to play here what timing a particular motor likes, carb settings, gear, tire height, the cam and how it was installed advanced or retarded.
I got in more little street skirmishes with this car than the GN because it didn't sound wild and even the 442 looked like chicken to every Mustang & Camaro. It looked stockish so they would just assume it was 307 powered.
In the GN they will give you a thumbs up and only rev at you if they are armed with a butt load of spray. In the Cutty they rev at you and grin.That CC big block shootout issue was one of my favorites. I like all the BOP & Cad engines too. Particularly the Buick & Cad for their lighter weight. As you pointed out they just cost more to build since the after-market is limited.
I'm sure my GP won't get any respect either once it's done. That's just more reason to go with quiet mufflers
I'm sure my GP won't get any respect either once it's done. That's just more reason to go with quiet mufflers
I didn't see the full article, can't seem to find the specs on the online version...what did they list the various weights at? I was under the impression that the Olds 455 was the lightest of them. Don't know if they're factory weights, and of course who knows how they're dressed, but I have, in pounds:
B-640
O-605-620
P-650
Cad-625
Regardless, with a few aluminum parts they're all under 600 pounds and within 5% of each other, and I'd still take any of them over a "popular" motor...
B-640
O-605-620
P-650
Cad-625
Regardless, with a few aluminum parts they're all under 600 pounds and within 5% of each other, and I'd still take any of them over a "popular" motor...
This is the list I usually refer to. I guess the Olds is lighter. I think I get confused with how light the Buick 350 is in comparison
http://www.carnut.com/specs/engdim.html
http://www.carnut.com/specs/engdim.html
Yea I have seen that before. I don't know where they got the Buick & Cadillac weights. They may have been weighed with starter or alternator or something. The Buick I saw was 605 and a Cadillac with the lighter brackets non smog & sheet metal pulleys and small harmonic dampner off a 425/368 instead of the earlier cast pulleys weighed 599. The BBC is always the heaviest but also has the cheapest and most prevalent aluminum intake & heads.
The Cadillac "standard of the world" at the time had the best quality factory cast & machined light high nickle block and heavy but super strong crank. Recently one was dynoed at 765HP with a modified factory crank & ungirdled block. But their problem is the intake to head alignment for air flow is not easily or inexpensively fixed and becomes a problem at 500HP.
Biggest bang for the buck improvement is getting a hollow 34 or 36 mm sway bar from an early 90s Camaro or Trans Am. The 36s only came from ones optioned with the TA's WS6 package or Camaro's 1LE package. But the last I knew you could still get it from GMpartsdirect.com cheaper than most of the aftermarket bars. Poly bushing and especially end links can also help a lot and are cheap & easy.
For springs generic gbodys all had super soft 346 lb rated springs with other length etc adjustments for v6 v8 AC etc. The performance Gs all had 420 lb rated springs and were ok with the big Caddy especially with the 36mm hollow bar & poly. The inexpensive Moog 5660 rated at 639 lbs and 5662 rated at 706 lbs are very common and excellent replacements. Not too stiff etc. Some also use the 5662 at 767 lbs but many say they are pretty stiff. I wouldn't want to go higher for fear of becoming bouncy and or harsh.
The Cadillac "standard of the world" at the time had the best quality factory cast & machined light high nickle block and heavy but super strong crank. Recently one was dynoed at 765HP with a modified factory crank & ungirdled block. But their problem is the intake to head alignment for air flow is not easily or inexpensively fixed and becomes a problem at 500HP.
Biggest bang for the buck improvement is getting a hollow 34 or 36 mm sway bar from an early 90s Camaro or Trans Am. The 36s only came from ones optioned with the TA's WS6 package or Camaro's 1LE package. But the last I knew you could still get it from GMpartsdirect.com cheaper than most of the aftermarket bars. Poly bushing and especially end links can also help a lot and are cheap & easy.
For springs generic gbodys all had super soft 346 lb rated springs with other length etc adjustments for v6 v8 AC etc. The performance Gs all had 420 lb rated springs and were ok with the big Caddy especially with the 36mm hollow bar & poly. The inexpensive Moog 5660 rated at 639 lbs and 5662 rated at 706 lbs are very common and excellent replacements. Not too stiff etc. Some also use the 5662 at 767 lbs but many say they are pretty stiff. I wouldn't want to go higher for fear of becoming bouncy and or harsh.
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