[Carmine]

Hi everyone. Quick question. How would make a 400 ci engine into a 455 ci engine?? Can it be done?? Would you use a 455 crank and bore it .30 over?? Would it be the same hp and torque as the 455?? Just curious. Thanks, Carmine.

[ponyakr]

A 4.21" stroker assembly will make a 455, out of a .030 over 400 block.

Yes, it would have the same power as a std bore 455. It would just have 3" mains, instead of 3.25" mains.

The 3" main 4.21 cranks now come in forged versions only.

http://butlerperformance.com/i-24453...tegory:1234863

The most popular stroker assembly, for lower budget guys, is a cast crank 4.25" stroke. There are lots of these engines running today. But, many consider the Chinese cast cranks total junk, and recommend forged only.

http://butlerperformance.com/i-24623...tegory:1234863

http://butlerperformance.com/i-24591...tegory:1234863

To build a slightly cheaper 455, you could buy a 4.21 stroker crank, then use resized cast rods, with Speed Pro L2359NF030 pistons. Then you'd have to buy the rings & bearings, and have a machine shop mount the pistons on the rods & balance the whole assembly.

The cheapest published price I know of for a forged crank is from Spotts. They also sell complete stroker assemblies.

http://www.spottsperformance.com/cranks.htm

The best price I know of for the Speed Pro 455 pistons is from Summit.

https://www.summitracing.com/parts/slp-l2359nf30

Most recommend a rod upgrade to at least the RPM 5140 forged rods. They're about $300 a set. The next step up is RPM H-beam rods, for $400 a set. Some like Eagle ot Scat rods better. They're a little higher than the RPM rods.

http://www.racingpartsmaximum.com/sa...tockrod-2.html

http://www.racingpartsmaximum.com/sa...elhbeam-2.html

Most guys also do not recommend the Speed Pro pistons. Instead, they prefer lighter pistons, which have floating pins, and thinner rings. There are several brands of these which are about $500 a set. If you decide to go with the lighter pistons & forged rods, the balanced Butler assembly deal will be hard to beat.

[Carmine]

A lot of good info and resources there. Thank you for taking the time to share. I don't have a GTO yet, but confident I will. Still looking for the right one. If it comes with a 400 engine in very good condition, then I will leave it alone. But if it needs rebuilding, I would go the stroker route. I did this with the 348/434 "W" engine in my '56 straight axle gasser. Has more power and pep then my '62 SS 409. Those stroker motors do run, Carmine

[b-man]

Probably less expensive to buy a 455 block and crankshaft and go that route.

That way you'd have a good cast factory crankshaft rather than a questionablee offshore cast.crankshaft.

[ponyakr]

Originally Posted by b-man

Probably less expensive to buy a 455 block and crankshaft and go that route.

That way you'd have a good cast factory crankshaft rather than a questionablee offshore cast.crankshaft.

That might be true IF, you can find a GOOD, rebuildable 455 block & crank, for a reasonable price. These are not available in many parts of the country now.

Paul Spotts sells 455 blocks for $600, and cranks for $300. So, that's $900, + whatever it costs to prepare the crank for an engine build.

http://www.spottsperformance.com/blocks.htm

http://www.spottsperformance.com/cranks.htm

He sells the forged Chinese stroker cranks for $650, & 400 blocks for $400. So, that's only $150 extra for a forged crank, less the cost of preparing the 455 crank. Plus you get the advantage of the smaller 3" mains. So, the 400 block/forged crank engine might actually be a little cheaper, UNLESS you can find a GOOD 455 core engine, real cheap.

I recently sold one for $500. But, that is only because I needed the cash, and there are VERY few Pontiac guys in my area.

[WDCreech]

Originally Posted by b-man

Probably less expensive to buy a 455 block and crankshaft and go that route..

I used a 4.25 stroke (offset ground) crank in a 455 block and at about 720 HP the block started to split between the crank saddles and the cam journals. So if you plan on making big HP, use a 400 block with a forged stroker crank.

['ol Pinion head]

Originally Posted by ponyakr

That might be true IF, you can find a GOOD, rebuildable 455 block & crank, for a reasonable price. These are not available in many parts of the country now.

Paul Spotts sells 455 blocks for $600, and cranks for $300. So, that's $900, + whatever it costs to prepare the crank for an engine build.

http://www.spottsperformance.com/blocks.htm

http://www.spottsperformance.com/cranks.htm

He sells the forged Chinese stroker cranks for $650, & 400 blocks for $400. So, that's only $150 extra for a forged crank, less the cost of preparing the 455 crank. Plus you get the advantage of the smaller 3" mains. So, the 400 block/forged crank engine might actually be a little cheaper, UNLESS you can find a GOOD 455 core engine, real cheap.

I recently sold one for $500. But, that is only because I needed the cash, and there are VERY few Pontiac guys in my area.

Totally agree with B-man!

Don, good Pontiac 455 cores are out there, just have to keep ones eyes open, also doesnt hurt to have friends in the know. Just because a builder puts up a price for his 455 block cores & crank cores, that does NOT mean that's the going price in every locale. Prices on bread & butter 455 short blocks have actually come down in many areas.

[ponyakr]

Originally Posted by 'ol Pinion head

Totally agree with B-man!

Don, good Pontiac 455 cores are out there, just have to keep ones eyes open, also doesnt hurt to have friends in the know. Just because a builder puts up a price for his 455 block cores & crank cores, that does NOT mean that's the going price in every locale. Prices on bread & butter 455 short blocks have actually come down in many areas.

OK, since that is the case. I'll ask for some examples. Everybody who has a cheap, rebuildable Pontiac 455 core, for sale right now, plesse post your price, and what area of the country you live in.

Since more Pontiac guys use this site than any other, if there are lots of these cheap 455 cores, this should reveal where they are, huh ?

Here's one in NJ for $1500.

http://forums.maxperformanceinc.com/...d.php?t=796887

Here's a crank for $175 + shipping, in DE.

http://forums.maxperformanceinc.com/...d.php?t=796486

Here WAS one for $700.

http://forums.maxperformanceinc.com/...d.php?t=796013

Here's one for $1450 shipped.

http://www.ebay.com/itm/Pontiac-455-...VX7VX-&vxp=mtr

Here's a block for $500 & a crank for $350, in Dallas. He's considering offers.

http://dallas.craigslist.org/ndf/pts/5829403909.html

Here's a rusty block & heads for $300.

http://dallas.craigslist.org/mdf/pts/5845899632.html

Every time I start adding up prices for an engine build, it seems that a Len Williams crate engine looks better & better.

http://lenwilliamsautomachine.com/455_Long_Block.html

http://lenwilliamsautomachine.com/455_Short_Block.html

Sandoval also sells cast crank 400 block stroker short blocks for $4k.

http://www.sandovalperformance.com/engines

[b-man]

The last two 455s that I sold went for $450 for the block and crank, that was a few years ago

I can't imagine paying more than say $300 to $400 for a good std bore 455 block or more than $150 to $200 for a good std/std 455 crank.

Good complete 455 core engines can still be had for $500 to $750. They're down in price nowadays because everyone is bypassing 455s to throw a stroker crank into a 400 block instead.

For a street engine making say 550 HP or less there's nothing wrong with using a 455 as the basis for your build, for higher HP engines opting for a 400 block with a forged stroker crank would be the better way to go.

[74 SD455 Formula]

I have a complete Carb to Pan 1972 455 out of a G.P..It was a good running motor when pulled. I am in Wisconsin and I am asking $1200.00.

[ponyakr]

Originally Posted by 74 SD455 Formula

I have a complete Carb to Pan 1972 455 out of a G.P..It was a good running motor when pulled. I am in Wisconsin and I am asking $1200.00.

Good luck !

I had a 455, which was smokin the RR of a '71 Safari wagon, when pulled. Tried to sell it for what I thought was a decent price--no sale. Wound up dumping it for $500, because of needing the cash.

I suppose it strictly depends on what part of the country you live in. No demand for Pontiac engines in my area.