Have a 67 bird numbers on motor block left side of waterpump on block are 0176218 under them is YY is motor a 400, or 428, or 455,
You need to see what the casting date is. That is behind the distributer. There was. YY in 67 that was a 428 and a YY in 73 that was a 400 and a YY in 74 that was a 455 all automatics.
You need the casting number and two letter code to positively identify a motor. The casting number is on the rear passenger side of the motor below the back of the head (or for very early 67 and before, near the distributor)
I also found block casting code on back of motor right above oil filter that is 500557 can not see numbers at dist/pad, can this be a 76 not a 73 motor
The mid 70's blocks should be no problem for building a moderate horsepower motor, just not a race engine, from what I've read. The bigger issue might be the motor mount holes. They changed the motor mounts from two bolt to three bolt in 1970. The early 70's blocks have all five holes and some of the mid 70's blocks do to. But there are some mid 70's blocks with only the three holes so you need an adaptor to bolt it up to an FGF.
The nickle content (strength) was gradually lowered over time as HP numbers decreased. Rated at 185 HP, the block is not the reason its rated as such. The reason for HP ratings is mainly found in the heads with the secondary being the cam.
You could take a set of #16 1968 360 HP GTO heads (incidentally only 330 HP in a Firebird) with a cam swap and have a 360 HP block. The reason pre 71 blocks were so desirable was that the net HP ratings were usually (and actually) off by upwards of 25% , thus the increased nickle in the block to offer a "margin of erro.r"
Would a 73 block suffice at 400 plus HP? absolutely.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
The nickle content (strength) was gradually lowered over time as HP numbers decreased. Rated at 185 HP, the block is not the reason its rated as such. The reason for HP ratings is mainly found in the heads with the secondary being the cam.
You could take a set of #16 1968 360 HP GTO heads (incidentally only 330 HP in a Firebird) with a cam swap and have a 360 HP block. The reason pre 71 blocks were so desirable was that the net HP ratings were usually (and actually) off by upwards of 25% , thus the increased nickle in the block to offer a "margin of erro.r"
Would a 73 block suffice at 400 plus HP? absolutely.
Additionally, the 500557 block has lighter webbing between the cylinder banks... decreasing its strength. However, it is widely agreed that these blocks will easily support a 500HP street machine.
My 2 cents...
...and if anyone is interested, I have a 500557 block available.
I'm a hobbyist. Not a professional. Don't be hatin'!
What is the date code on the block by the distributor? It will look like something D126.
Also their is probably a partial VIN down lower on the block next to the timing cover. See what that is also. It can tell you what the engine came out of.
I have a 69 Firebird where the previous owner changed the engine. They put a 1976 400 in it. Has anyone else done this or heard of any one doing this and are you aware of any fit issues? Is the 76 Engine physically larger?
All Pontiac V8 engines, with exception of the crappy 301, basically share the same engine block. Differences are crank journal and bore sizes.
Late 70's blocks do not have the motor mount holes tapped for 1st Gen Firebirds. They make adapter plates.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Put a 1977 557 block in a 67 bird using the adapter brackets they sell. One small snag was one of the bolt holes in the block was not drilled and tapped to attach the new adaptor. I have my own way around using these adaptors that don't always work.
On the front I have 0276694 WT, On the back I have K208 and 9790071. From what I found its a 68 400 WT 360hp made on November 20 1968. Is that correct? I was told it possibly came out of a GTO.
K should be October they skipped I. So, October 20, 1968. I'm seeing that it could be a 350 HP GTO engine as opposed to the 360 hp. Either way, yes should have been out of a GTO.
1968 400 Coupe, verdoro green, black vinyl top 1968 400 Convertible, verdoro green, black top 1971 Trans Am, cameo white, auto 1970 Buick Skylark Custom Convertible 350-4(driver)
In 1971 all manufacturers started making lower HP motors just by changing the heads, they increased the area above the pistons raising the cc numbers and that lowered compression ratios from 10.75-1 to 8-1 or so. They also ran lame cams unless you had a HO, trans am, etc.
You could easily make this motor scream by changing the heads and cam, just don't push it, unless you're balanced etc you shouldn't push any V8 past 5000 unless you have lots of cash to blow on another engine. You could easily get this motor in the 350-400hp range with tons of torque.
.... looking at comments on the web, certainly seems the 500557 aint the pick of the litter.
