454ci in a '66

[Tom Bryant]

If you want to keep the Powerglide that should be no problem. The Pg was the automatic trans in both '66 and '67 Corvettes with hydraulic lifter big blocks. In '66 both the 427/390 (L36) and the 427/425 (L72) were rated at 465 pounds of torque. The difference being that the 390 horse was rated at 3600 rpm and the 425 was rated at 4000 rpm. With the size of tire you will be able to put under a stock midyear body you will loose traction long before you break the trans. It will take a lot of hard starts and just plain abuse to distroy that Pg if it's in good condition.

If you have any doubts take it to a trans shop that builds racing transmissions for a high performance rebuild. Keep in mind that the Pg is one of the most popular transmissions in many classes of drag racing including rails and gasser type cars. You will find them behind almost any engine you can think of, even big block Fords and Chrysler products, that are making huge hp and torque numbers and hooked up with big slicks. They use them because they are durable and with only 2 speeds their times are more consistent.

You didn't mention what your Corvette guy was going to give you with that 454 build. What parts are he going to use? What kind of hp and torque numbers is he talking about? Is he figuring on hooking it to the Pg and building it accordingly? A 427 and 454 look the same on the outside so you could dress the 454 up in origional 427 accessories and it would take a numbers guy to tell the difference. In this case numbers don't matter anyway. The 427 has better high rpm potential but the 454 makes it's grunt lower where you do 99% of your driving. Also 427 builders are harder to come by these days. I suggest you take a few rides in some built up 454 cars too. Back in the day I had a '70 El Camino SS 454/450hp LS6. I shifted the M22 between 6000 and 6500 normally and quite often at 7000 depending on the heat of the moment. It's all in the build.

The '73 -'75 454 passenger engine is a good builder. The low power numbers of these engines in stock form don't mean a thing once you tear them down and start building from the bare block. Take a look at the specs for that 454/425 crate engine. It will run on regular unleaded and idle like a stocker. The crate 572/650 horse is said to idle smooth while burning pump gas. Big cubes, lower compression and proper camshaft and head selection are the key. How about the Viper or that V16/1000hp Caddy concept car. It's loud but smooth and can be fueled at the pump.

No matter how much technology improves there is one axiom that remains constant. There is no substitute for cubic inches.

Tom

 

[BlueAgave66]

Wow, very informative response, thanks. I am waiting to hear back from the vette guy today or tomorrow with the specs. Glad to hear about the PG and the fact I might be able to keep it. That would save a few dollars. I know we have to change out the radiator and probably suspension. Also the hood. I don't plan on using side pipes but reworking and using the tail pipes. Not as throaty but still enough to wake up the neighbors if I want.

 

[IH2LOSE]

I don't plan on using side pipes but reworking and using the tail pipes. Not as throaty but still enough to wake up the neighbors if I want. [/B]

If you decide to go with the big block I have a set of big tube staull headers welded into side exchaust pipes with driver quaility (actually lower then drivers quaility) side cover you could purchase to save the exspence of getting big block exchaust manifolds.Go to the secound page of c1 and c2 parts for sale

 

[BlueAgave66]

Thanks, will see where things go.

 

[396 RAT]

"Keep in mind that the Pg is one of the most popular transmissions in many classes of drag racing including rails and gasser type cars."

I know PG's can be built to take amazing amounts of HP & TQ,
I just didnt think a stock PG out of a 66 300hp 327 would be up to the task. Live and learn.......
Thanks for the info.

 

[magicv8]

...and don't forget to get an externally balanced (for 454 crank)plate to mount the torque converter on.

 

[BlueAgave66]

That's the second time I got that advice. Interesting thing is that the vette guy specifically mentioned that his 454ci is setup as an internally balanced motor although the original 454 was designed to be external. What is the implication of internal vs external balance?

 

[magicv8]

Not enough weight on the GM 454 crank to balance the stroker - so they put weights on the flex plate/flywheel.

I believe 454 Cranks without external weight needed are mods (heavy metal added to holes in counterweghts) or some aftermarket stuff.

My car had a bored 454 (468) without the externally weighted th400 flex plate when I got it. My dentist put my fillings back in, and I got a Muncie.

 

[BlueAgave66]

454ci in a '66 vette

Ouch, sounds like a problem. To make matters more confusing, I had someone suggest today I forget about the BB and get a 350ci/400hp crate motor. He said it would be an easier conversion, not require any additional suspension, new hood or radiator. He said with a little work on the rear end, that motor and my PG would give me a thrill similar to the 454 or 427..but without the noise. Plus it would be gas pump friendly, probably cheaper and provide a warranty. Thoughts from those experts who have been very helpful so far?

 

[IH2LOSE]

I would highley recomend the 350/400 motor to you.

But understand it wont be the same as a HIGH winding b/b.

but it will still be a blast with out all the extra work.decide what you want out of the car.Dont have a monster motor built with solids in it and only to have to spend the weekend adjusting them

 

[396 RAT]

Adjusting lifters for most mid year owners is an hour every year or two. No big deal. Do many of us really drive our mid yrs 15000+ miles per year?

 

[magicv8]

I have to agree with ih8tolose - especially since I bagged my BB and run with a 350. I drive a lot, so the mileage and ability to run on the 86-88 octane high test I find in small towns in the Rockies was a necessity.

I discussed a destroker crank and dished pistons for the 427 and decided I could buy 3 SB engines with the money it would cost to make a really streetable (daily use in adverse conditions) BB.

I have never regretted using the SB mule engines to tour the USA - especially with the A-C running in city traffic on a 104F day.

 

[396 RAT]

I agree, if you want to drive long distance, get good mileage, etc build a small block. May be a much better option since you are starting with a small block car. You can build a screaming 350
for 1/3 the cost of a serious BB.
If you want a weekend car to scare your self in, get a solid lifter
BB ground pounder. I had a great time in my 65 365 coupe.
But they really are 2 different cars. And as far as BB's inherent over heating and poor handling, both are myths.
Small block cars are fast, but did not turn in faster lap times
over BB cars in road racing, slalom, or at the drags.

 

[BlueAgave66]

454ci in a '66 vette

So, what I hear you guys saying is that the 350/400 should give me a rush similar to the 454 without the teeth rattling but I can still get on the turnpike and visit relatives 50 miles away.....and save a few bucks in the meantime.

 

[magicv8]

That was the conclusion I came to. Your teeth will only rattle if you don't get a balanced 454 - internal or external. My 468cid with a 4.56 rear only gave me 6mpg city or highway. The SB is 12 city 16-20.5mpg on the highway (depending on speed, 20.5mpg below 70mph, 16mpg above 100mph with a 3.08 rear). I had 11 inch tires on the rear with the BB and the rear kept passing me - usually on the left. Overheating is never a problem until you turn on the A-C.