Thread: 454 4 bolt or 2 bolt

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i have a 671 dyers supercharger with 2 750 mighty demons for rectangular port big block chevy. I am wanting to get on with the motor build but dont know what i should get for a 454 block. Should i get a 2 or a 4 bolt 454 block. I am wanting to shoot for somewheres in the 650-700 horsepower range and of course want the thing to stay together. Are the 2 bolts able to be built to take that much power or do i definatly need a 4 bolt? I understand you can splay the 2 bolts but does that make it unfeasable enough to just say forget it and pay a little more and buy the 4 bolt to begin with?

Also, What is the difference in the normal deck height block and the tall deck. Will they both make good blower motors or is one better than the other? Do i need a certain intake?

Thanks

I can only say from reputation in SBC's and BBC's that splayed main bolts are stronger ,splayed main studs even more so and that from my stock car days that stock 4 bolt SBC's are weaker across the caps than 2 bolts .That said, it means nothing when refering to a BBC. I am running studded 2 bolt mains in my 461.

If you are doing it from scratch and have the money, go with a 2 bolt block and have splayed caps installed, If money is a huge issue the 4 bolt block with new arp bolts will stay together.

i have used many two bolt blocks with studs can take alot of hp.if you do not have a 454 two bolt block less if you can buy one very cheap? hard to find...you should look in to the price of the splay caps and a line bore you very well may not be to far off buying a new world block that can take more power and a bigger bore the older blocks that have been over bored are getting hard to find .the tall deck 427 10.200 deck block should be cheaper then a 454 4bolt main 9.800 deck block if you have the room for the 427 tall deck can work good but you will need longer push rods and rods pistons and spacers for the intake or tall deck blower intake and a slip collar dist and if you find the right tall deck there cut for a 4.000 inch crank and with very small bit of work can swing a 4.500 crank.i would stud the two bolt and stay a round 600 hp and you will be fine with the stock 454 two bolt

Originally Posted by Dgas56

I can only say from reputation in SBC's and BBC's that splayed main bolts are stronger ,splayed main studs even more so and that from my stock car days that stock 4 bolt SBC's are weaker across the caps than 2 bolts .That said, it means nothing when refering to a BBC. I am running studded 2 bolt mains in my 461.

see this is where i seem to have this problem in my head with week points because if the sb stuff has less material when being a 4 bolt then should it not be the same with the 4 bolt bbc or is there that much more material in a bb that it is not an issue?

I have a line on a fresh 60 over 4 bolt 454 block that is already studded with arp for 1000 cdn or i can buy a friends 76 camaro that is rotted out and been sitting for 15 yrs in a field for 1000. He has no idea about anything as far as the motor goes, other than its a 454.I am assumeing its a 2 bolt block. Do i take a chance on the camaro stuff or buy the 60 over block...decesions, decesions

Well.......... if it were me...... I'd go the camaro engine - if its never been apart. Your starting with a std. bore so YOU can go from there. As for the other .060 doesn't leave you much more material to overbore (although I've seen race engines much bigger) but it's all what your design for the engine is.

Best of luck.

Regs

ps: I ran a 2 bolt 60 over 54 with prostock epd heads & intake on the street & strip in the 80's....... I buzzed that thing to 7500 regularly & never had an issue. Car & engine sold & was used for many yrs. afterwards.

Originally Posted by REGs

Well.......... if it were me...... I'd go the camaro engine - if its never been apart. Your starting with a std. bore so YOU can go from there. As for the other .060 doesn't leave you much more material to overbore (although I've seen race engines much bigger) but it's all what your design for the engine is.

Best of luck.

Regs

ps: I ran a 2 bolt 60 over 54 with prostock epd heads & intake on the street & strip in the 80's....... I buzzed that thing to 7500 regularly & never had an issue. Car & engine sold & was used for many yrs. afterwards.

well here is the deal if you block rock the 454 short fill and put steel caps on it will take what ever you can throw at it .the deal is with hi rpm and hp the caps will move but this is the hi side of 700+hp and the rails of the block will flex i have many many two bolts out there that run past 7000 rpm and make 700 hp EZ but there is more then just block work on the bore out can go 070 and 100 over and 125 bore but getting one out that far i would sonic check the 060 and the 070 is not to big of a deal the big block has the best bottom end of any block out there and in no way should be compared to a sbc. i have fixed many bbc when they have kick out rods or lost pistons a stock sbc you would be scraping the block. i have many 489 and 496 and a513 that used stock blocks the 070 bore 4.375 stroke =513cid and runs like a bear . i may just put a 4.500 crank in one and bore it out to 100 short fill it and the steel middle main caps to make a 535 CID with a stock 9.800 block

I have built many 2 bolt changed to 4 bolt angle mains--It is my perferred method--however, the stock 4 bolt bbc with studs can be used for well over 1000 hp without cap walk if you stay out of detonation---
The bore issue isn't an issue at the 060-070 area---generally not even at 100 or 125 over

If it wasn't for shipping to Canada I'm sure you could get a block from down here a lot less $$$

i have two454 and i am in mich not to far ?? well i have two bolts that are 650to 700 hp never worry about needing the two more bolts or block rock but the bottom of the block could use more iron from block flex that why i said a world block may not be to far off for money less you can do all the block machine work your self sooooo if you short fill and steel splay cap it and stud it it will take alot i was a poor white boy i could never afford the 454 4 bolt main blocks and built alot with just two bolts mains and GM bolts that took a hell of a beating .i made two bolts in to 4 but i just move up to the bowtie s block s when they were cheaper to buy then a beat up used 454 4 bolt main block

thanks for all the info people. I will keep posted on my decision and i will have a lot more questions during this build. This is my first ' big block", and "blower",build experience.

The bbc bowtie blocks were great!!!!had cylinder walls and weren't too awfully heavy as the Dart and other aftermarket blocks

We had three of the first 7 tall deck bowties, as they weren't legal yet in most places but we could run them in UDRA

Originally Posted by jerry clayton

The bbc bowtie blocks were great!!!!had cylinder walls and weren't too awfully heavy as the Dart and other aftermarket blocks

We had three of the first 7 tall deck bowties, as they weren't legal yet in most places but we could run them in UDRA

yes and they were abit heaver then a stock 454 block.i do not think much at all about dart that nice 1 inch+ ball mill on the out side of the oil rail this very nice when you lose a rod it takes out the oil pan rail . if dart stop the ball mill job i would like there blocks more...i would take a world pro block or merlin lll any day over a dart . the bow tie was not the best but good . i could buy them cheaper then a 4 bolt454 block guys had them all over from bay city to flint they were not hard to find . dart and world did see the short coming of the GM bowtie and built a better iron block... just very heavy that why i love my donovans i can pick one up even with my bad back not like them darts or worlds

o.k people

So i went with the 4 bolt block for ease of getting it home and more space in the garage. The next step is a rotating assembly. I called my speed shop today and he gave me a price on an eagle assembly but the only thing i dont like to much is the pistons. They are 10.3-1 and i have always thought blower motors to be lower compression motors. Am I right or will i get away with 10.3-1 compression? I should say to, that the r/a is to build a 498 motor. One other thing i should ask( because i forgot to ask my guy today) was ...does the block need to be ground to clear the 4.25 crank?

i have built 10to1 blower engines would be nice to be at 9.5 no more then 10.1 what are you doing with this engine race street /strip ? for cutting the block if you use a H beam NO you should not but you may have to clean up the block for the counter weigth in the back of the block and if you use a beam rod with a thru bolt rod and not a cap screw rod then you will have to do some small triming

this motor is going to be both a street and a strip motor. I am looking for around 700 streetable horse but it will see a fair bit of strip use as well and thats why i dont mind spending some $$$ on parts that will last and stay together. The rods that come in the rotating assembly are h beam rods, so i guess thats a bit of a bonus?