Hi Folks,
I was wondering if any of you folks have a rough estimate of the horsepower a properly prepped 350 4-bolt main block can take. I searched but didn't really find an informative answer.

Imagine the bottom end has ARP studs, and it is used in a boosted application with a .030 overbore (no 7500+ rpm).

I am familiar only with Ford blocks, the 351C blocks generally good for a reliable 550-600 hp with 2 bolt studded mains, the early 351W blocks up to 800 hp with 4-bolt conversion.

I am curious to hear, particularly from Turbo s-10. I have acquired this very mint 350 very cheaply, as well as an '81 Malibu Wagon and a '65 toploader 4-spd I have lying around. I was thinking of turbocharging the motor with a DIY fabricated kit and two Garrett hybrid turboes, hence my concern for block strength.

I would like to make lots of power but by the same token not build a time bomb, or at least one that ticks too rapidly :~) $2500 aftermarket blocks kills the budget pretty quick.

Cheers,
Andy

if you stop and think that back in the day when 327's ruled and they were all 2 bolt,racers used to routinely run 750 h.p. and now you have nextell cup cars running 750 but those blocks are slightly beefier.you can also get cap straps for 2 bolts or even turn a 2 bolt into a 4 bolt which is stronger than a factory 4 bolt anyway.ask anyone who runs a 2 bolt 400 block.

http://www.hotrodders.com/t57867.html

Opinions will vary, but I found one source that stated: "4-bolt blocks with ARP main studs are good to 700 HP, and are good to 8500 RPM"

Ed www.edgesz28.com

Hey Guys,
Thanks for the link to the previous thread. Didn't realize it had been addressed before, maybe I need to get better acquainted with the "search" function.

Anyways, I think the 4-bolt will fulfill my needs fine. If I come upon a good deal for a Bowtie I might pick it up.

Thanks for all your input -

Andy

y two turbos? the whole twin turbo concept is so overrated. Just get one bigger turbo and its more than you will ever need. The only use of TT is for looks.

Not nesecarly true. If you go too big you will get turbo lag. By running multiple turbos you are able to series them to eventually power a big turbo.

Where are you getting your info at ? Do you have any evidence to back up this statement? I am sure the fellers over at Lingenfelter would be quick to disagree with your statement.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

The reason they do it is because it is easier to fit two small turbos than one big one on a corvette. But overall it is an unefficient design...the reason a lot of people with twin turbo cars convert to a single turbo design.

and here...



that nova runs low 7s...one turbo




Dan Millen...one turbo...and up until a few months ago the world record holder on 10.5 tires...7.1@198


But they are as big as basketballs lol

Packaging is the big issue for two turbos. It is easy to stash them in the front, away from the accessory drives, and save the fenderwells.

A single turbo is the way to go, efficiency-wise, although those single turbo setups for drag cars are not real streetable. Many don't start to spool because their huge size (due to the size of the inducer) until 3500+ rpm, and then boost comes on like a freight train. Plus, there is no way to fit a basketball size turbo in a car with fenderwells and stock front accessory drive.

Anyways, I am familiar with the implications of each setup. I was more concerned with blowing up the foundation of the whole effort, the block, though. I need to start shopping for a good fuel injection computer, I was thinking the Electromotive Tec(3) with DIS, seems to be a reasonable $1700 or so.

Cheers,
Andy

oh my god. thats awesome!

The maximium hp levels that the OEM block will contain will vary with the type of use its destined for. High rpm launches have been breaking those blocks since the 60s without turbos.

In fact, you can occaisionally pull those blocks out of the original car and find cracks in the main webbing at the factory hp ratings.

The term "reliable" is important in that what I consider reliable and what you consider reliable may differ. For me to convey reliability to you, you'd need a "benchmark" of what I consider a reliable street motor.

To me, a reliable street performance engine would have to go 100,000 miles to meet my definition of reliable. I think this is where all of the differing opinions come into play. Some folks obviously consider shorter service lifes of engines as being reliable.

That being said, I think you could make that 4 bolt block live 100,000 miles at 500 hp if you did not use the engine for drag racing and carefully maintained it. You'd really have to pay very close attention to the tune up so as not to get into detonation under boost and beat the webbings, crank, bearings, rods and pistons right out of it. You can easily get to this power/reliability level without a turbo.

If on the other hand, you wanted to go to 800+ hp reliably, you'll need to spend some money on a block to know for sure that you wont have cast iron pieces on the pavement.

Its no secret that guys are getting 1100-1200+ hp out of blown injected small blocks on alcohol but they are far from 100,000 mile motors and the owners are never surprised by block failures.