To Stroke or Not to Stroke - That is the Question

[MWGT40]

As well as making substantial modifications to the suspension and brakes on my GTD, I am now looking at improving the performance of the engine. I have a 302 SVO engine at present with a Holley 650 Carb. I am probably going to go with the Eidelbrock performer package which should give at least 350 BHP with my existing setup.

From what I read and hear, I can easily improve the power (but particularly the torgue) still further to over 400 BHP by stroking the 302 to 347 with a stroking kit from the likes of PAW in the US. These kits are not that expensive from what I see on the website (around $1,500).

The question is, are there any disadvantages to stroking the 302 out to 347 - and if there are not, why aren't more GTD owners doing this (particularly in the UK)?

 

[Neal]

Martin,

The 347 stroker w/ 3.4" rods moves the wrist pin into the oil ring on the piston. This is not desireable from a longevity standpoint. There are companies that overcome this issue with special pistons and rods. A 331 combo doesn't have this issue. A 302 can make over 400HP w/o stroking it. Airflow and cam are key.

 

[Hershal Byrd]

Neal,
You hit the nail right on the head ! The
302 is capable of plenty of HP without
stroking. I decided on a 306 that is built
by Gordon Levy. The numbers on this engine
are impressive. Gordon's knowledge of
cams and heads is awsome. Perhaps he will
read this and post a comment on the specs.

Hersh

 

If you really want to check out stroking and different kits. Check out flatlander racing as well.
http://www.flatlanderracing.com/

 

[Julian West]

Martin,

Would you be prepared to share details of your suspension & brake mods? off list if you prefer?

I'm trying to decide which route to take, wether to simply live with the stock geometry & high unsprung weight & just do the brakes, *or* change the uprights and fit rose jointed wishbones....

 

[MWGT40]

I know that I can get 400 BHP out of a 302 without stroking. Frank has advised that with Victor Jnr heads, I should be able to able to generate this kind of power. However, most of this will come above 4,000 rpm.

Because the car will be used on road as well as the track, I was looking for more power lower down i.e. more torque hence why I am considering stroking.

How much does the kit that you mention to avoid the longevity problems cost?

Thanks for your help.

 

[MWGT40]

Julian,

I am going with the brakes from HiSpec. On the front will be the "Racing 6" 6 pot calipers with 335mm discs. On the rear will be the "Racing 4" 4 pot calipers with either 300mm discs or 335mm discs (I have 17" wheels note).

As for the suspension mods, I am replacing the existing bushes with nylon bushes and the existing Spax shock absorbers with Koni ones which are externally adjustable and have separate adjustment for bump and rebound. I may look at moving to rose jointed suspension later, but I do not want the car to be too hard for the road.

Frank Catt is carrying out the work for me of course (way beyond my technical limits unfortunately)!

 

[Julian West]

Martin, Thanks for the info. 17" wheels seem to be the way to go for ultimate performance. I'm sure you'll stand the car on it's nose!

I'm a bit concerned about the stock geometry.. looking at club pictures, one solution seems to be fitting spacers in the pickup points. I'm they work, but must take alot of time to set up, as opposed to simply adjusting a rose joint. With rose joints I guess there is a fairly hefty cost issue & ride quality will suffer... ho-hum, decisions decisions!