Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Engine (http://www.hotrodders.com/forum/engine/)
-   -   700hp small block chevy (http://www.hotrodders.com/forum/700hp-small-block-chevy-182850.html)

blownmazda 08-16-2010 06:36 PM

700hp small block chevy
 
hello im wondering if its possible to get around 700hp from a 355 sbc with a 6-71 blower? id be using it for drag racing mostly and possible spirited street driving. im just trying to see where i can go with my motor due to recent need of rebuild. just seeing if anyones done this before with advice, ive read a few magazine dyno test that show 355 can do it.

bigdog7373 08-16-2010 07:00 PM

Lots of boost, light weight components, full roller valve train, good flowing heads, and most importantly perfect timing.

bentwings 08-18-2010 10:00 PM

You forgot LOTS of cash. :pain:

Oh yes a new wheelbarrow for hauling the scrap away when it comes apart. :pain:

cobalt327 08-19-2010 06:54 AM

Quote:

Originally Posted by blownmazda
hello im wondering if its possible to get around 700hp from a 355 sbc with a 6-71 blower? id be using it for drag racing mostly and possible spirited street driving. im just trying to see where i can go with my motor due to recent need of rebuild. just seeing if anyones done this before with advice, ive read a few magazine dyno test that show 355 can do it.

I'm going to guess that this is just a "toss it out there and see" type of question.

If you're serious, you'd do well to do as much research as possible into what's required. A thread on this forum will not be sufficient- unless someone was willing to dedicate HOURS of their time to educate you on all the nuances involved.

700 HP requires good parts- the number of production parts that would go into an engine like that- if I built it or oversaw the build- would be counted on one hand, if that. And unless there were a reason like rules for a particular racing class I was trying for, I wouldn't build a 700 HP SBC in the first place. IMO, this is BBC territory.

There's no sense in building the engine so small. In that you're going to be using an aftermarket block anyway, and an aftermarket rotator, you might just as well build at least a 427 SBC from the get-go.

Now, there are guys who'll tell you that cast cranks or OEM steel cranks w/o a BBC snout or w/o dual keyways is fine, and that 2-bolt production blocks are fine, that cast pistons and OEM rods are fine, etc. ad nauseum.

Reality often clashes w/these "recommendations", however. This type of build offers ZERO margin for ANY error. Even if it is perfect AFA the tune goes, there's no guarantee the crank won't fail or the piston's ring lands won't pinch the rings or the rods won't come apart. This can happen even w/GOOD parts if there is one little failure- like in fuel delivery or ignition timing.

Often what you will find at the bottom of all this fertilizer, is the HP they THINK they're making, isn't anywhere near what they ARE making. If all you want is a short-fused, cross-your-fingers-and-hope engine, I cannot offer anything but a head-shaking "good luck". Keep the OEM parts below 450-500 HP at the most and you'll be OK. Go to 700 HP and you'll need a magnet to pick up the litter.

If you want something that will actually make 700 HP w/a modicum of reliability, be prepared to get into some serious cash outlay. Like 5 figures' worth. Just the induction system could go $5K w/o a problem.

Now, all that said- why don't you start out w/a stout 355 w/about 400-450 HP to get you started. If you've never driven a decent car set up w/450 HP, you'll be surprised how "lively" it can be.

In other words- walk first- THEN run. ;)

F-BIRD'88 08-19-2010 11:03 AM

Colbalt... when your $5K motor comes unglued you are out $5K.

When a cheapy stock/near stock based motor comes unglued you are out a few hundred dollars.

Yes you can make 700hp from a 355 with a 671
but you are not going to do it with 350hp parts

the best high flow 23deg sbc heads money can buy.

two 750cfm blower tuned carbs

mechanical roller cam with 250- 265 @.050 .600 lift.

14 psi boost.

forged pistons, blower preped crank

The easiest, most dependable lowest cost over time method to do this and get 700+hp is to use methanol fuel.
10:1 cr for methanol.

A realistic 650+hp can be achieved with 7.5:1 cr and 94 octane gas.

cobalt327 08-19-2010 11:18 AM

Quote:

Originally Posted by F-B88
Colbalt... when your $5K motor comes unglued you are out $5K

When a cheapy stock based motor comes unglued you are out a few hundred dollars..

?? Who's $5k 'motor'?

The only mention I made of $5K was the cost of the induction system.

And either way, $500 or $5000, the engine comes unglued- which was my reason for pointing what I did, regarding the quality and cost of the parts needed to make a reliable 700 HP.

Which I personally wouldn't do w/a 355 SBC anyway- unless for some unknown reason I just had to have some of a racing class that required such a combination.

700 HP? Make mine a BBC, thanks just the same. ;)

F-BIRD'88 08-19-2010 11:23 AM

Quote:

Originally Posted by cobalt327
?? Who's $5k 'motor'?

The only mention I made of $5K was the cost of the induction system.

And either way, $500 or $5000, the engine comes unglued- which was my reason for pointing what I did, regarding the quality and cost of the parts needed to make a reliable 700 HP.

Which I personally wouldn't do w/a 355 SBC anyway- unless for some unknown reason I just had to have some of a racing class that required such a combination.

700 HP? Make mine a BBC, thanks just the same. ;)

I agree with that. I would start with a BBC too for 600+ hp.

The basic engine is just so much stronger.
The cylinder heads are far superior.

cobalt327 08-19-2010 11:30 AM

If you want a recipe for stupid power for low bux, look no further than for a turbo like the dirt-cheap fleabay T3/T4 hybrid turbo w/3" outlet, an external wastegate and a pair of $100 stainless steel one-size-fits-all turbo headers.

Cobble this all together onto a 350 SBC w/a Summit camshaft kit and make over 600 RWHP. Cost WAY under $2500 not including the junkyard engine.

F-BIRD'88 08-19-2010 11:56 AM

You would need a a pair of the T3/T4 hybrid turbos for that power level but ya I hear ya. :thumbup:

turbolover 08-19-2010 12:38 PM

Quote:

Originally Posted by cobalt327
If you want a recipe for stupid power for low bux, look no further than for a turbo like the dirt-cheap fleabay T3/T4 hybrid turbo w/3" outlet, an external wastegate and a pair of $100 stainless steel one-size-fits-all turbo headers.

Cobble this all together onto a 350 SBC w/a Summit camshaft kit and make over 600 RWHP. Cost WAY under $2500 not including the junkyard engine.


Or spend a little extra to run 20G turbos with 10cm housings, or HX35's or one of many other options and make more power for less than a grand more.

Turbos will become just as much a part of building a car as the transmission is. There is a LOT to be had there and people are finally beginning to see that.

cobalt327 08-19-2010 12:52 PM

Yes, 2 of them- my bad.

I'm an E-85 source away from throwing caution to the wind and turbo'ing a 6L LS truck engine along w/a set of the L92 heads.

mokicruz 04-28-2012 03:18 PM

Quote:

Originally Posted by cobalt327
Yes, 2 of them- my bad.

I'm an E-85 source away from throwing caution to the wind and turbo'ing a 6L LS truck engine along w/a set of the L92 heads.

Do you remember hotrods Junkyard jewel article where they took an oil burner from a junk yard with over 150,000 miles re-rung it, put in main and rod bearings then did their nitrous and a cam thing to it? It made three full pulls on the dyno with a large manifold and carb then ran it half the summer before it got to sick to run 19's anymore.


All times are GMT -6. The time now is 10:11 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.