75 Corvette Tuning

75corvette

Newbie
Points
56
From
norfolk/cambs border
Car
corvette
Hi guys,

I own a 75 chevrolet manual 4 speed convertible which has had several mods made to the 350 small block already, These include: edelbrock performer heads, holley Carburettor, Hooker headers, side pipes, and MSD distributor, electronics etc.
I am now looking to increase its performance and driveability without making significant alerations to the chassis etc.

Any thoughts?

I have been looking at maybe a five speed manual box, altough I recently saw a 56 Chevy saloon fitted with an electrically operated overdrive unit between the box and rear axle ( Gave it 8 gears!!!)

Also I have looked at the possibility of adding twin electric fans and then fitting march pulleys to release im told around 17bhp!:rolleyes:

I am looking for any suggestions to accomplish the above without wasting time and money going down routes that maybe some one else has tried and found to be a waste.:(

Help.

Regards

75Corvette
 

Wcnwzrd

Track Warrior
Points
77
From
Casa Grande, Arizona
Car
95 300zx TT (RIP)
depending on what you mean by modifying the chassis. you can have the engine ported and balance, bored out, change the material of the internals, change the compression ratio. supercharger kit (quite spendy to get installed), transmission swap, pulley kits (they change the material of the pulleys so they are lighter and better overall). hope this helps. i used to have a 73 but it had the 400 in it.
 

obi_waynne

Administrator
Staff member
Moderator
Points
887
From
Deal, Kent UK
Car
A3 1.4 TFSI 150 COD
Moved this into the Chevrolet forum as well - you might get a few more replies in here.

Great car to start out modding. The fans wouldn't pull that much from your crank. Electric water pumps are worth looking into.

A supercharger would be a good idea. You get quite a big power gain from that.

Do you know what power you are running at the moment?
 

Sid447

Torque Junkie
Points
252
From
TRNC
Car
VX-Series 2 V8 M6
Hi guys,

I own a 75 chevrolet manual 4 speed convertible which has had several mods made to the 350 small block already, These include: edelbrock performer heads, holley Carburettor, Hooker headers, side pipes, and MSD distributor, electronics etc.
I am now looking to increase its performance and driveability without making significant alerations to the chassis etc.

Any thoughts?

I have been looking at maybe a five speed manual box, altough I recently saw a 56 Chevy saloon fitted with an electrically operated overdrive unit between the box and rear axle ( Gave it 8 gears!!!)
Also I have looked at the possibility of adding twin electric fans and then fitting march pulleys to release im told around 17bhp!:rolleyes:
I am looking for any suggestions to accomplish the above without wasting time and money going down routes that maybe some one else has tried and found to be a waste.:(
Regards 75Corvette
Depending on what you have available to spend on the car,

If you are after a better manual transmission, Tremec make both a 5-speed and a 6-speed for these:-

http://www.ttcautomotive.com/English/products/tremec.asp

If you get serious about either a TKO or a T56 talk to these people:-
They'll supply everything needed:-

http://www.richmondgear.com/01transmissions.html

Fitting under-drive pulleys, slow down both the water pump and the alternator, along with the PAS pump. Not a great idea, they have recommended rated speeds for normal operation for a good reason.
(Under-drive pulleys are popular with the drag-racing fraternity who mainly use their cars exclusively for for short engine operations, where doing this kind of thing isn't so critical as it's used to free up some hp for acceleration).

The gear splitter you mentioned doubles the amount of gear ratios in a vehicle, it comes from here:-

http://www.gearvendors.com/mhfacts.html

Electric fans along with the wiring, relays and fans cowling would be a pretty expensive way of getting a modest power gain. You would be better off looking for a clutch drive fan if you have the fixed drive type fitted atm.

The Generation 1 SBC 350 is pretty old tech now. It is difficult to get much more power out of them than you probably already have. The best and easiest power gain you could do for these, if it is an original '75 engine is to convert it to full roller rockers.
The original GM rockers were made from pieces of stamped steel and were approximately 1.5:1 ratio, though this would vary, because they were not very good at all.
There are magazine articles which show just by fitting a set of roller rockers, a gain of over 25hp.

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=1412-16&Category_Code=

http://www.compcams.com/information/Products/rockerArms/ProMagnum.asp


Along with a hydraulic roller camshaft conversion kit.

http://www.chevyhiperformance.com/techarticles/148_0307_converting_hydraulic_roller_cam/index.html

Doing both of these his would net you a serious gain in power without "tuning" it any further.

Here's a good link page for you to browse:

http://www.grapeaperacing.com/links/index.cfm
 
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helphos

Wrench Pro
Points
43
From
Olney MD, USA
Car
BMW 325 XI
I had a 75 Corvette many years ago (bought new). I autocrossed it for a while and found that the best mod was a rear sway bar. Those cars didn't come with them generally and they understeered like pigs. Once I put the sway bar on it was a different car.

Good luck!:)
 

yankfan100

Tuner
Points
20
From
Taplow,Bucks
Car
MG ZS IXL DTi
ok, ive had lots of yanks,,to get more ponnies for free try this, turn distrib: up from,, i think your running 8 datc,, to 22-25 atdc, but u will run very hot so take the stat out, may have to alter fuel flow oh & the twin kenlows r a must,,,d'you run inboard computers for the fuel system , my caddy seville 76 did so i had to fool it into thinking it was only giving half the amount of fuel,,,,i played some more & after 3 yeays got 425 bhp & only having a through exaust hand bulit was my only big expence..keep me posted.. used to run a 65 Buick GS Coupe 401, she ran 660 ponnies,, pure evil......
 

akus

Newbie
Points
1
From
norway
Car
1974 corvette 383
Bye a HP36 383 stroker engine from ATK. 435 HP 475 L|B torqe.Foged rods and pistons.Both summit and ecles sell them for $4420
 

TCJBOLDIE

Torque King
Points
652
From
Brisbane
Car
JB Starion
Has anyone mentioned fuel injection and an aftermarket computer for better ignition and fuel supply control and drive-ability ?
 
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