[68WarDog]

What year(s) did the 455 blocks come with 4 bolt caps?
My friend is asking for its value and plans to sale . It comes as a bare block and caps only, and.has been sonic tested for cracks. Any ball park value

[Tim Corcoran]

I'd say around $300 but I will give you &325 just because I'm a nice guy.

[John Milner]

I would say $750-$1,000 for a real 4 bolt 455 block. Maybe more if it has a block code and date that someone is looking for.

[Navy Horn 16]

They were almost all drilled for 4 bolts. Not all got the 4 bolt caps. 4 bolt caps are available in the aftermarket, but that adds an align hone to the machine shop bill.

[Joe's Garage]

Every block (#9799140) we've ever touched that came out of a 1970 Pontiac had 4-bolt mains. There is info that some came drilled for 4-bolt but only had 2-bolt caps installed - we presume that those were the low-performance, big car versions. We've never touched any of those.

All the 455HO (#483677 and 485428) blocks in 1971 and 1972 were also 4-bolt mains. I believe that some of the standard 455s also got 4-bolt mains, but it appears to have been random.

And, of course, the SD455 blocks were not only 4-bolt mains but had reinforced webbing in the lifter galley and more meat elsewhere.

Many of the 1971-74 'normal' 455 blocks (#485428) were drilled for but did not have 4-bolt caps.

Every Service Replacement 485428 block we've seen (at least a couple dozen) had 4-bolt caps, although we've heard claims that a few were built with 2-bolt caps.

I'm pretty sure that everything after 1974 was 2-bolt mains.

A good, standard-bore 4-bolt main block is worth AT LEAST $1k - could be considerably more if a desirable date or engine code.

SD blocks are at least 5x that.

[68WarDog]

Will post code and bore size tomorrow. The block has its original 4 bolt caps

[Skip Fix]

The 455 in my 78 TA I got from a 70 big car. drilled for 4 bolts and has only 2 bolt main caps. I had a later 455 block still missing after a few years at my machine shop-was only 2 bolt caps also. The 72 HO block I had(cast on Feb 29th! was 4 bolt caps.

[Gary H]

Originally Posted by Joe's Garage

Every block (#9799140) we've ever touched that came out of a 1970 Pontiac had 4-bolt mains. There is info that some came drilled for 4-bolt but only had 2-bolt caps installed - we presume that those were the low-performance, big car versions. We've never touched any of those.

All the 455HO (#483677 and 485428) blocks in 1971 and 1972 were also 4-bolt mains. I believe that some of the standard 455s also got 4-bolt mains, but it appears to have been random.

And, of course, the SD455 blocks were not only 4-bolt mains but had reinforced webbing in the lifter galley and more meat elsewhere.

Many of the 1971-74 'normal' 455 blocks (#485428) were drilled for but did not have 4-bolt caps.

Every Service Replacement 485428 block we've seen (at least a couple dozen) had 4-bolt caps, although we've heard claims that a few were built with 2-bolt caps.

I'm pretty sure that everything after 1974 was 2-bolt mains.

A good, standard-bore 4-bolt main block is worth AT LEAST $1k - could be considerably more if a desirable date or engine code.

SD blocks are at least 5x that.

Just to add a little more to the mystery on these blocks, I recently sold a 70' 455 SR block, standard bore, #9799140. It was actually cast in 70' and had a 70' date code. When I bought the engine it had the correct #64 heads on it, oil pan etc.. I was really surprised, and disappointed when I pulled the pan off and discovered it was drilled for 4 bolts but had 2 bolt mains

[Half-Inch Stud]

For Durability sake, i favor my 2-Bolt undrilled Mains 455 block, 1971 casting.

[firechicken]

My 70 block was drilled for 4 with 2 bolt caps. I added 4 bolt program caps...

[64speed]

73 Grandville block. Drilled for 4 but used factory 2 bolt caps

[Gary H]

In addition to my post above, I pulled a 70' code correct 455 from a 70' GTO a long time ago and it was a drilled for 4 bolt but 2 bolt cap block. Around the same time I pulled a 70' Gran Prix with a correct 455 in it. It was a 4 bolt main block. Both with #64 heads. Go figure!

[pokey1]

In 1980 I pulled the motor I have from a 1970 station wagon, 455 block drilled for 4 bolts and with 2 bolt caps. I kept the 2 bolt caps and put ARP studs in.. Has worked great and still going now..

[Dragncar]

Anyone ever sonic check a 70 4 bolt block ? Wondering if anyone has had any luck taking the .070 +. I have one, 060 over. Have a 73 std 2 bolt too.

[steve25]

In terms of production line motors, the 455 was no different then any 400 or 428 block in that only the highest hp versions and or the cars that had 4 speed manual trannys got the 4 main caps.

The factory 4 bolt caps are made of nodular iron and are very strong, in fact I don't think I have ever seen one fail unless there was the failure of the block taking place first, or a seized Crank leading to there going south!

During the last production run of the 455 for 1976 cars there where no 4 bolt main 455 blocks, nor where the outer 6 holes drilled, but left unused.

If you are building any motor that will see close to 600 hp or more that has unused main bolt holes (especially the long stroke 455 ) you should get grade 8 Allen head bolts and red loctite them in to greatly stiffen up the main Web area from flexing around those open unused holes!

[Gary H]

Originally Posted by Dragncar

Anyone ever sonic check a 70 4 bolt block ? Wondering if anyone has had any luck taking the .070 +. I have one, 060 over. Have a 73 std 2 bolt too.

I know a few here have actually gone .100 overbore to 4.250. Not necessarily with a 70' block but with any block after first sonic checking it. There's actually one here in my home town that's in a race car that's .100 overbore. It's been running fine at that for years. It is hard blocked though and has a lifter brace in it

[78w72]

Originally Posted by 68WarDog

What year(s) did the 455 blocks come with 4 bolt caps?
My friend is asking for its value and plans to sale . It comes as a bare block and caps only, and.has been sonic tested for cracks. Any ball park value

isnt sonic testing for thickness & magnaflux for cracks?

[steve25]

Yes!

[Steve C.]

Originally Posted by Dragncar
Anyone ever sonic check a 70 4 bolt block ?

18 years ago I bought a '70 455 block and its original crank, both for $300. The block had never been bored and the crank was uncut. I had the block hot tanked then all the cylinder walls were sonic checked on their front wall, rear wall, outside wall and inside wall. Checked at the top and halfway down on all these locations. For the most part the measurements taken on the front side of all cylinders were the lower numbers, again measured at the top and halfway down.

The passenger side bank on the front: lowest was 0.122, the highest was 0.257. The average was 0.165".

The Drivers side bank on the front: Lowest was 0.120", the highest 0.235". The average was 0.153".

For the '600 hp' engine build the block was bored to 4.181" then it was filled to the freeze plugs.


.

[steve25]

With wall thickness numbers like that I am very happy that even with taking my 455 out to just .030" over that I chose to half fill it!!