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Question,
I have a non-numbers matching 1966 corvette coupe
when original it was 427 390 hp car, the motor in the car is not the original 427, it’s an 1969 427
The existing 427 motor runs good, doesn’t smoke, has good oil pressure and it’s not a leaker, meaning not leaking oil everywhere
my plan is or was removing 427 over winter months, replacing some of the gasket painting it up and putting it back in
about the motor i have no idea how many miles are on it, as I have no history of the car. I did remove a valve cover and looked inside and its clean
I also have a brand-new still in box Blueprint 454 4 bolt main crate engine, it's of the 500 hp 500 torque variety
What would you do keep the 427 or replace it with 454?
This 454 will accept the shorter valve covers, just saying
For some reason, I can’t explain I always thought the 427 was superior to the 454, not sure why, perhaps cause its balances inside not outside
All words of wisdom welcomed
Thanks!
This isn't quite six of one and a half-dozen of another. Those engines have different personalities. If you want a very high-winding engine that performs well at the top end, the 427 is the better choice as it has larger bore but shorter stroke. If you want stump-pulling low-end torque then the 454 is your boy. Because I have one, the 427 would be my choice. Ironically nowadays neither of these engines are considered all that big. As an added bonus, if you stay with the 427, you don't have to change emblems.
If you are pulling it, replacing gaskets (don't know why if it is not leaking........) and you pull the oil pan, I'd remove a couple bearing caps and look at the health of the bearings. I'll do this every now and then. Most times everything is just fine, but on one occasion, a "professionally rebuilt" engine with very low miles had several rod bearings worn to the base metal......... Not good......
I wanted to paint the engine, clean up front and paint it as well, chassis and suspension where applicable, that why removing. Also it's an a/c car but someone removed all the components except firewall box, thought easier job engine removed
I agree with the other two replies, stick with the 427. It's far more similar to what was installed originally, and keeps the performance in line with how it was intended.
Once the existing 427 comes out, what were your plans other than gaskets as needed? Were you intending on checking the bearings as has already been asked?
Since this 427 was in the 66 BB before you bought it, I'm guessing you don't have any idea what cam is in there or condition of the heads? Maybe before you tear it apart,
do a compression test and if you're inclined, maybe a leakdown test as a way to verify how good that engine is.
Considering the labor is the same, one engine out, one engine in, I'd be tempted to put in the new Blueprint 454.
My 66 L72 Roadster lost it's original engine many years ago, either late 70s or early 80s and in it's place is a very good running, but sedate mild cammed '68 396.
Good oil pressure, smooth idle etc. It aint broke so I don't need to 'fix it' but...I have a 66 4-bolt #942 block on the stand and will be assembling a solid lifter
version of the original L72 engine and that will eventually go in to replace the 396. To me, the comparison is...mild 325 horse 396 to higher horse 427, 427 will go in.
Good luck and by the way, we do love pics, love to see your A/C L36.
Mike T - Prescott AZ
You didn't mention why you have the 454.
I had a lazy 305 in my car when I bought it. It was a very clean engine ...just had no pop. Rather than bump it up a bit I bought the BP 383 and the 305 was sold within a few days to offset the cost. That said...I'd also stick with the 427.
Since you have some concerns about the 427 why not pull it, freshen it up and have a basically rebuilt motor?
I bought the 454 for a 32 Ford 3 window I was building
But i broke my hand which resulted in multiple surgeries
The hand will never be 100% again so I scraped the 3 window and bought this car, much less work fixing vs build from nothing, at least what I keep telling myself
One of the things that you should consider is what the cruising RPM will be. Depending upon your differential, you might be operating where the longer stroke might not be as comfortable and really getting into fuel guzzling territory. Of course an overdrive transmission will cure that. The other thing is that a brand new engine is much easier to sell than a used one and could fund a good chunk of your project.
It has the original rear in it, 3:08
I think that gear either could work 54 or 27
However it doesn't have original trans, very odd to me it has a t10 out of 63 Corvette, very odd I thought at least to me
Did a 427 car come from GM with a 3.08 gear?
A 3.08 is going to be hard on the clutch from a standing start , you might need that 454 with 500 lbs of torque to get that thing moving.
I had a '64 Malibu with a GM 454 LS6 450HP/500 Torque and a 4 speed. I found that a 3.42 gear worked good for all around city and highway driving.
Did a 427 car come from GM with a 3.08 gear?
A 3.08 is going to be hard on the clutch from a standing start , you might need that 454 with 500 lbs of torque to get that thing moving.
I had a '64 Malibu with a GM 454 LS6 450HP/500 Torque and a 4 speed. I found that a 3.42 gear worked good for all around city and highway driving.
yes and I believe what was recommended with AC
and for what its worth keep the hood shut on that beautiful car and enjoy it as is for as long as possible
which motor to use
