View Full Version : Blown lq4 how much can the block handle


Ls sn95
04-19-2012, 09:17 PM
Lq4 block 427 CI Callie's dragon slayer crank,Oliver I beam rods,and wiesco pistons how with a F1R at about 20 pounds of boost goal is 1100 hp I kno these blocks can handle power just want to make sure it can handle this without having to go to a Lsx any help would be great



Thanks

9sectruck
04-19-2012, 11:31 PM
if the bore is 4.125 it will not live at all
seen sum threads with 408 making 1500 plus, half filled 1/2 studs and girdle

Fbodyjunkie06
04-20-2012, 01:40 AM
I thought you said on the bullet that you were wanting to go to 427" and not already there.

I would keep it at 4.030 bore if at all possible and keep the stroke at 4" or less.

Ls sn95
04-20-2012, 08:47 AM
I thought you said on the bullet that you were wanting to go to 427" and not already there.

I would keep it at 4.030 bore if at all possible and keep the stroke at 4" or less.

Well that was the plan got a quote for the short block on to go 440 and from lme and it was 8500 wanted to be less than that on the short block so I'm trying to go budget On the block and all out on the rotating assembly

02anti_vnm
04-20-2012, 09:05 AM
I don't think the block will be an issue. The heads will lift way before you hurt an iron block but I would get the mains pinned and go 1/2 head stud as preventative measures against some other troublesome areas

87silverbullet
04-20-2012, 09:09 AM
If you go anything more than a 408 you won't have a good enough compression height on your piston to run that much boost. They will melt like a foam cup on fire.

If I were you, I would look into an AES 390 shortblock using your block. You will get the best bang for your buck with that setup. It will have a good stroke and a nice compression height on the pistons. I think there is one guy here already making over 1100 rwhp with one.

AES Racing
04-20-2012, 07:59 PM
Lq4 block 427 CI Callie's dragon slayer crank,Oliver I beam rods,and wiesco pistons how with a F1R at about 20 pounds of boost goal is 1100 hp I kno these blocks can handle power just want to make sure it can handle this without having to go to a Lsx any help would be great



Thanks

That is probably about the worst combination possible.

390ci would be good, but i'm partial here:swing:

We build 427 LQ9 blocks too, that block with that power, thinner cylinder walls, thinner stroker pistons, will wear the pistons quicker and eat itself up in oil consumption.
427 LQ9 is best left to a weekend car, N/A, small nitrous shot.

cashbrown
04-21-2012, 09:53 AM
Just my 2 cents, but at 20PSI your gonna be close to or are going to lift the heads on a 4 bolt configuration. Save your money and get an ERL or LSX 6 bolt block. In the grand scheme of 1100 HP the cost of the block isnt that signifigant. So I would say either lower your goal to a lower HP for reliability or risk pushing it to the edge where sooner rather than later you will find the limit.

Fbodyjunkie06
04-22-2012, 02:03 AM
With a copper o-ring set-up and the right head, with good internal support so it doesn't move around on the deck will support 1600hp if the maintenance is done right and head gaskets kept up with.

Ask Fireball.

Surface area is the problem on a small block and big boost. Smaller bore helps, but this is why a big block per say has an advantage for example.

87silverbullet
04-22-2012, 02:09 AM
Just my 2 cents, but at 20PSI your gonna be close to or are going to lift the heads on a 4 bolt configuration. Save your money and get an ERL or LSX 6 bolt block. In the grand scheme of 1100 HP the cost of the block isnt that signifigant. So I would say either lower your goal to a lower HP for reliability or risk pushing it to the edge where sooner rather than later you will find the limit.

^^^This was the case 5 or 6 years ago. Not today

With a copper o-ring set-up and the right head, with good internal support so it doesn't move around on the deck will support 1600hp if the maintenance is done right and head gaskets kept up with.

Ask Fireball.

Surface area is the problem on a small block and big boost. Smaller bore helps, but this is why a big block per say has an advantage for example.

^^^This is today. Alot of progress on sealing a 4 bolt has been addressed and the power levels of a 4 bolt set-up are being being pushed higher and higher.

Ls sn95
04-22-2012, 09:23 PM
^^^This was the case 5 or 6 years ago. Not today



^^^This is today. Alot of progress on sealing a 4 bolt has been addressed and the power levels of a 4 bolt set-up are being being pushed higher and higher.

As far as the precautions that's I need to take to prevent major problems on this block do you have any advice I need to take in so this block holds up and the heads do not begin to lift

1fast bird
04-23-2012, 07:45 AM
As far as the precautions that's I need to take to prevent major problems on this block do you have any advice I need to take in so this block holds up and the heads do not begin to lift

For an F1R I would build a stock stroke 370 or go with the 390. Use a good forged crank and have the main caps pinned to keep them from wanting to walk around. Having the block and heads o-ringed and using 1/2" head studs will keep the heads from lifting and pushing water. All this is good to a point, but will cost you close to the same as building a LSX which already has doweled mains and the obvious 6 bolts per cylinder......

cashbrown
04-23-2012, 02:35 PM
have the main caps pinned to keep them from wanting to walk around. Having the block and heads o-ringed and using 1/2" head studs will keep the heads from lifting and pushing water. All this is good to a point, but will cost you close to the same as building a LSX which already has doweled mains and the obvious 6 bolts per cylinder......

This is the point I was trying to make. :swing: