Author Topic: Engine setback in GT?  (Read 6904 times)

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Offline Carl Johansson

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Engine setback in GT?
« on: August 26, 2008, 08:15:24 PM »
I've looked through the book and can't seem to find anything that would preclude me from moving my engine back 4 - 6 inches (to accomodate a big block).  I will have to fab up a new firewall -  but thats OK - the stock unit is plastic and full of holes!  GT/ c -  changing to GT/A

Carl Johansson
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dwarner

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Re: Engine setback in GT?
« Reply #1 on: August 27, 2008, 01:55:54 AM »
You cannot move the the engine back in GT, it is a Production Category class. If you swap in a BB for the OEM SB the front plug must be loctaed in the OEM position.

DW

Offline Plainview

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Re: Engine setback in GT?
« Reply #2 on: August 27, 2008, 09:58:34 AM »
So it the car is say a Ford Probe GT, you could put a big block Ford motor in the car and still be ok in the production class?

LittleLiner

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Re: Engine setback in GT?
« Reply #3 on: August 27, 2008, 11:03:01 AM »
So it the car is say a Ford Probe GT, you could put a big block Ford motor in the car and still be OK in the production class?

No.  The probe GT would not run in the GT classes because it is a not a 2 passenger car.  It would run in the Production classes.  Unlike the GT class you cannot swap an engine in the Production class.  in the GT classes any 'swap' must be with an engine from the same manufacturer. 

Did I get it right Dan?

dwarner

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Re: Engine setback in GT?
« Reply #4 on: August 27, 2008, 12:30:40 PM »
Thats correct. Just because the name includes the the letters GT does not mean your car will be classed as a GT/MS.

In the GT classes the engine "swap" must remain in the manufacture's production inventory. A Ford Indy engine from the 60s is not allowed as a GT swap.

DW

Offline Carl Johansson

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Re: Engine setback in GT?
« Reply #5 on: August 27, 2008, 12:54:35 PM »
OK Dan,
Just to make sure I'm headed the right direction.  It is an 88 corvette,  I am planning on putting in a chevy 454 Big Block -  so the engine swap is OK -  but I cannot set it back to clear the pulley from the front crossmember -  is that correct?

see thats why I come here -  you guys stop me from making all sorts of mistakes!

Carl johansson
Carl Johansson
 Auberry Ca

dwarner

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Re: Engine setback in GT?
« Reply #6 on: August 27, 2008, 12:57:22 PM »
The engine must go to were the OEM placement was. The firewall, floorboards, etc may be cut to fit at the rear of the engine.

DW

McRat

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Re: Engine setback in GT?
« Reply #7 on: August 27, 2008, 02:00:48 PM »
Unless you already have the engine, the newer LSx engines are the same physical size as the SBC yet can be ordered from the factory up to 427ci as a production engine, and up to 455? ci aftermarket.  The 427 crate engine is 505HP before a tuneup, 530 after tuning in mild street trim.  While it is an OEM production Corvette engine, it is based on the C5R endurance racing engine, so should operate at all altitudes reliability for years at stockish power levels.  It should have acceptable life at 750HP due to titanium rods, dry sump, and other racing tricks unseen before in a domestic car engine.  But it is a digital engine that you tune and datalog with a notebook computer which scares some folk off.

Offline Carl Johansson

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Re: Engine setback in GT?
« Reply #8 on: August 27, 2008, 02:26:51 PM »
The engine must go to were the OEM placement was. The firewall, floorboards, etc may be cut to fit at the rear of the engine.

DW
forgive me on this dan,  so if i used the engine mounts on the engine and put them in the stock mounts on the frame -  would that be OK?

PS - engine is already bought, put together mand dynoed (to answer the other poster)

carl Johansson
Carl Johansson
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Offline 38Chevy454

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Re: Engine setback in GT?
« Reply #9 on: August 27, 2008, 04:16:52 PM »
The engine must go to were the OEM placement was. The firewall, floorboards, etc may be cut to fit at the rear of the engine.

DW
forgive me on this dan,  so if i used the engine mounts on the engine and put them in the stock mounts on the frame -  would that be OK?

PS - engine is already bought, put together mand dynoed (to answer the other poster)

carl Johansson

This would put your engine further FORWARD.  The relationship between the bellhousing face and the engine mount location is the same for a SBC or BBC, the difference is the BBC extends further forward.  In other words the mount location on the side of the block is more in the middle of the block on the BBC.

What was stated earlier, your BBC front spark plug location has to be in the same position as the original SBC.  Which in itself is a bit hard to determine since the BBC are angled, I would use the centerline of the plug hole as the reference location.  By doing this you "should" be close to original clearance on your front pulley, espcially if you use the short water pump set-up.
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Offline jimmy six

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Re: Engine setback in GT?
« Reply #10 on: August 27, 2008, 05:08:32 PM »
I believe in the GT class where BB's have replaced SB's; the BB's were fit to the same motor mounts and stock location of the bell housing or auto trans. Just because of the difference of the length of the engines the BB first spark plug would be farther forward than the SB. On the ones I have inspected or certified there was never any question arising concerning this....JD
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro

Offline SPDRACR

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Re: Engine setback in GT?
« Reply #11 on: August 27, 2008, 05:55:05 PM »
Carl, From a Corvette novice was a Big block engine even offered in that year ? If not you just put your self in Modified sports and the fire way question MAY be a non issue. Remember this is from a Roadster guy ,what do in know. Eric
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Offline 4-barrel Mike

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Re: Engine setback in GT?
« Reply #12 on: August 27, 2008, 06:25:46 PM »
"Engine swaps are permitted as long as they are of the same manufacturer (e.g., Ford into Ford, Porsche
into Porsche, etc.)"

Mike
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canadianrocky

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Re: Engine setback in GT?
« Reply #13 on: August 27, 2008, 08:35:30 PM »

***What was stated earlier, your BBC front spark plug location has to be in the same position as the original SBC.***

Ok, but nowhere in the rule book does it say this.

The question I have is as follows.

Does there exist another rule book that is used for specific rule interpretations, are rules interpreted as per car as it is presented, or is the rule book strictly enforced?

The way I read it for GT, is that there would be no reason why a Chev V/8 could not be put in a Pontiac Solstice. Chevrolet and Pontiac are both manufactured by General Motors.
« Last Edit: August 27, 2008, 08:39:06 PM by canadianrocky »

Offline Carl Johansson

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Re: Engine setback in GT?
« Reply #14 on: August 27, 2008, 10:21:22 PM »
Hey Canadian Rocky,
I agree with you.  I have spent the past 2 hours looking through the rule book -  checking every definition referenced etc,  and I cannot find anywhere where it says you cannot setback an engine in a GT car.  I find no mention of it in the production category -  5E. pgs 70 -71.  And I find no mention of it in the GT class rules 5E3, pgs 74 - 75.  BTW it is here that specifically allows the engine swap (which is disallowed in the production code) change to a big block previously referenced by 4 barrel mike!

So I hoping Dan or someone else can site a location ofr the specific place I can read about not allowing setback engines in GT class!

Carl "now I'm really confused" Johansson
Carl Johansson
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