331 Stroker

[woodstock]

Anyone driving a 331/390hp in their roadster? I'm seriously considering that engine built by the Engine Factory. I'd be interested in hearing what led you to this engine choice, what transmission you chose and how it's working out. I'd be using it for the street, a few long drives and at times, some spirited driving. Thanks!

[edwardb]

Personally, I think a 302 based stroker is almost an ideal setup for these cars. They're compact, good value, parts are plentiful, a nice power bump over a 302/306 setup, and the power band works really well. Early strokers had issues with rod angle, but that seems to be a non-issue with the right pistons and especially with a lower displacement like a 331. I went with a 347 in my Mk4 build. After talking to my engine builder, did upgrade to a DART block. But a 331 in a stock block, kept below 400 hp or so, is a reliable and well-proven setup. Around 400 hp seems to be about the tipping point for a stock block. North of that and (at least according to my builder) you are pressing your odds for the famous 302 block split. But for street and "spirited" driving (e.g. not tracking it) you should be fine with a mildly stroked stock block. I would think a T-5z would work fine with that setup with street tires. 3.55 diff would also work really well. Good luck with your choice.

[woodstock]

edwardb-Thank you for your insightful comments! As you know , it's a big decision. Ed

[68GT500MAN]

The 331 is a very nice combination for these builds.
Doug

[skullandbones]

I've heard good things from anyone who has had one. I asked Karen S why she used one and she said they were basically "bullet proof" so for track use it was very popular. It is a step up in performance from the 302. I have a bucket list item that keeps running through my head. It's a Dart block based 363. I would love to have that with a Lunati cam. The nice thing is you can have the compactness of the 302 and still have a serious punch. That may be more than you are looking for but it sure would add another dimension to your roadster (long drives, street, and the track!). The reason I mention this is everyone decides they need more HP even after you have done your research! Good luck on your choice. Also, The super T5 would give better peace of mind.

WEK.

[Avalanche325]

To me, the big reason to go with a 331 over a 347 is that the block does not have to be clearanced. This is great if you are installing a stroker kit yourself and don't want to modify the block. If you are getting a new professionally built engine, it would be no big deal to go up to 347. If you see how much clearancing is actually done, it is not much. You will get some more HP and torque for not much more money.

I think 400hp is being very conservative for a stock block. At least I hope so, I am at 500, which I think is the top of the safe zone. Many people are pushing more and have no issues, but more HP is always more risk. A DART block is a seriously nice piece. It adds around $2200 to the build, but then you can go up to 363 CI and will likely have that block for the rest of your life.

It is surprising how quickly you get used to the HP. I am doing bodywork so am off the road right now. After two months, I took my car out for a run around the block. It seemed like a monster, now that I wasn't used to it.

With any engine size there are mild, medium, and wild build levels. So take that into account, not just the CI.

With all of that said. There is nothing wrong with a 331.

[woodstock]

Anyone driving a 331/390hp in their roadster? I'm seriously considering that engine built by the Engine Factory. I'd be interested in hearing what led you to this engine choice, what transmission you chose and how it's working out. I'd be using it for the street, a few long drives and at times, some spirited driving. Thanks!

Thanks for your input everyone!