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Discussion Starter · #1 ·
hello guys

thank you all for this great site
been lurking for more than 3 months and I have gained a lot of knowledge from you gays
I can say it is one of the best and most informative sites on the web

thank you again :)

.................................

I am building a turbocharged chevy powered 1985 RX7
as you know it is a very light car :D

I have an old 350 goodwrinch engine
and recently I have scored two 400 blocks
one is standard while the other is 0.020 overbored

I am looking for 800-1000 hp
so I will use 4 bolt splayed caps on the one I will choose
it will have AFR 210s and DIY sequential EFI ( Genboard )
and of course all forged internals

I know with the torque of the 400 I will defintally have traction problems and I have read that turbo motors like bigger bores than longer strokes so I am thinking to destrok the 400 and do a 377 :D !


do you think the 400 block with its thin cylinder walls can handle 15 - 25 psi or boost on that power level? or I will be better with the little 355 ?

don't say aftermarket block because it is too expensive for me

any input appreciated
 

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aftermarket block :thumbup:

I dont think the 400 would be able to handle 15psi let alone 25psi. If you want to keep from blowing the motor, the 355 would be a better starting point. 1000hp out of a 355? Not to say its impossible, but it is unlikely. There was a website posted somewhere on here with a 427SBC twin turbo vette that dyno'd at 1200hp. But I believe (sorry) it was an aftermarket block.
 

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Discussion Starter · #3 ·
hello





I can reach 1000 hp with my combo even on a lil smaller engine
but for now I will be satisfied by 700-800 rwhp :thumbup:
( until I have the $$ to buy an aftermarket block :D )

thanks for you reply
 

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You should be okay with a stock block and splayed caps. It will require a tall grout to stabilize the cylinders. As with anthing, material fatique will probably eventually take place and the block will crack somewhere eventually. The big bore short stroke works very well with turbo engines. You dont need the longer stroke for torque since you can simply add boost to increase torque. But, the 400 will make some difference in power output and you can get a little more power and a little lower RPM. 23 cubic inches is just not going to make that much difference one way or the other. Pick your poison and go with it. It just really does not matter much.


Chris
 

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TurboS10 said:
You should be okay with a stock block and splayed caps. It will require a tall grout to stabilize the cylinders. As with anthing, material fatique will probably eventually take place and the block will crack somewhere eventually. The big bore short stroke works very well with turbo engines. You dont need the longer stroke for torque since you can simply add boost to increase torque. But, the 400 will make some difference in power output and you can get a little more power and a little lower RPM. 23 cubic inches is just not going to make that much difference one way or the other. Pick your poison and go with it. It just really does not matter much.


Chris
There ya go... response from an expert at this.. :)

Personally, I still wouldnt go with the 400. Because If I did something like that, I'd want high pressures and long life. Which is why I said 355. I'd be to scared of cracking the walls of the 400 after a couple miles.
 

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Discussion Starter · #10 ·
hello guys



I will stick with the 355 because as Chris said there is no difference
and strong low end torque will cause traction issues for me :pain:
also 355 blocks are plenty everywhere and CHEAP :thumbup:



thank's a ton for your advice :)
 

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TerroRx7 said:
hello guys



I will stick with the 355 because as Chris said there is no difference
and strong low end torque will cause traction issues for me :pain:
also 355 blocks are plenty everywhere and CHEAP :thumbup:



thank's a ton for your advice :)
He was talking between the 400 and the 377. I am pretty sure chirst runs a 400 block.
 

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I do run a 400, but only because I had it already when I started the buildup. I would not go buy one for the application. I would actually like to do a small cube 330 cid range engine next time with a destroked 350. I am going to run this one till it breaks first.

Chris
 
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