Speed Pro forged aluminium pistons - Any good?

Anyone have any experience/history using Speed Pro forged aluminum pistons in their Mopar? Specifically Small block application.

I think those are the same as what used to be called TRW. If so, used them a lot in the distant past. No problems at all other than they were heavy and we often had to cut the valve reliefs deeper for roller cams.

Bill

All the federal Mogul, Seal Power, Speed Pro pistons are made in India now, all of them have the dry film lubricant on them They are not as good as they use to be
You can do a lot better with KB forged Icon line or any of the other American made forged pistons like SRP, Diamond, Ross and so on

Below are a couple of photos of the Speed Pro Piston.

I ran the Speed Pro pistons in the TT440. The first set I had was treated viciously and went through a LOT of detonation as I was learning the ins and outs of turbos. When I pulled them out they were scuffed and 4 of them had rings so badly broken they fell out in pieces. Still, the pistons held together.

The second set saw higher boost pressures (surged to 21 psi at one point) and put up with alcohol injection at 15 psi. They were still running in the engine when I sold the car a couple years ago.


They aren't be best thing out there but they put up with my abuse.

Wiseco Street ProTru so much better deal-- light-- with rings and priced right

Pistons are already installed in the short block... friend is looking at purchasing the assembly and wanted my take on the setup. I was not familiar with the brand. So I decided to seek expert advice from the Moparts forum.

I ran their forged flat tops in a 360 for ten years. No valve reliefs and heavy as boat anchors, but held up just fine. Never saw and power adders though.

Decent forged pistons in my opinion, but heavy as others have said. Not bad on a budget, moderate performance engine.

X3 on the weight, iirc mine were 2355's (was 30 yrs ago).

I must be getting old.

The older stuff is good when it was made here.

If you don't mind me asking sir, what is the problem with the dry film lubricant?

I don't believe they are made in India any longer.
They had lots of problems with them when they made that change, and lost a lot of sales as a result.
I can't remember where I was told they're coming from now...... But I think it's Mexico.

The only problem I had was that with the coatings like those is you can't get a decent measurement for piston to cylinder wall clearances
I had to replace two pistons for a friends roots blown SB Chevy that he had bought the older TRW turbo pistons without the coating 20+ yrs. ago, I couldn't buy them anymore so we ended up waiting a little over 6 months for those Speed Pro replacement pistons due to the manufacturing being moved to India and not being told the new replacement ones only came with the coating

In general, coated pistons skirts are good. It's supposed to reduce piston-to-wall friction.

History: When I started the real HP car stuff in 1972 Speed Pro and TRW were the two manufacturers of forged pistons for American engines. That is, if you could get them for your engine. They were reasonably priced. If you couldn't get them for your engine then you went to Arias or Venolia or Forgedtrue and paid a lot more. That was it.
They were strong but heavy, same weight as the cast pistons they replaced. There were guys who earned a living lightening TRW and Speed Pro forged pistons for racers.

Then I was out of the game for a while.

Now, Federal Mogul makes Sealed Power for regular performance, and Speed Pro for the high performance crowd. Ironically. the Speed Pro pistons many times use the old TRW part numbers. But TRW pistons are no more. The pistons are still heavy and stout but now they cost quite a bit more than they used to, counting for inflation.

There has sprung up a crop of aftermarket forged piston makers who for a couple of hundred dollars more make a superior piston, in terms of weight and suitability for much higher performance. They used to be double the old TRWs, but now they aren't so much more cost. They have flexibility in specifications and there are many part numbers for shelf stock pistons. Changes to the pistons can sometimes be done for a few dollars or free, so your pistons will be a lot closer to what you need.

In the case of a 383 which has Speed Pro pistons already installed, if it's for a street engine they are about unbreakable. It's not worth trashing them to spend another $800 on a set of "better" pistons.

As far as the carping on the Speed Pros, most of those come from real racers or people who use their engines hard. The JE, SRP, Wiseco, ProTru, Diamond, Icon, Ross, etc pistons fit their needs better. If one was building a 383 from scratch I'd suggest using one of these, but mainly for compression reasons. You can tailor the CR by making modifications to the pistons that are not available from S-P.

R.

I built a stroked 4.0 I6 for my jeep about 14 years ago. The kit I used came with speed-pro pistons and it is still working great.

As posted they are good pistons, your look like the old trw and would have the triangle T on the underside.

Yes they are heavy, these are for a lil 318 project and at 767 grams are only 40 grams lighter the the domed venollia? I have in a 360 currently.

You can still find them new (old) for $300 on ebay semi often.

Since they have been made by so many there is alot of confusion on piston to wall specs as some of the newer spec less.

Ive a set in my v code runner I turned backwards and they have been in since 86 and rattle like a old gm diesel but they run hard.

These were within 3 grams of each other out of the box and easy to get within 3/10s.

I have these in my 493 and I really couldn't believe the level quality for the price

Gus

Dogdays makes lots of good points. These days the speed pro's are so costly as well as being made overseas so you have to really consider if they're worth it. The TRW's used to be nice forged, inexpensive pistons.



A lot of guys like to comment on the weight of the old TRW's but the reality is they were about the same weight as the stock pistons they replaced. There are still guys running old school stock stroke 440 combos with the TRW's running the 11's.

Its been shown over the years and ive seen it first hand if you take out the shortened compression height of the stroker pistons that factors in them being really light a oem CH performance piston vs a old trw produces a very minimal difference in performance and if good machine work is done and some common sense is used they are not too hard on parts either.

I myself will use all the old trw-s at $300 a set for street builds vs the now $800 diamonds that were $500 just a few years ago for the same piston.

Look how the stock 340-s ran and reved and look at there oem piston weight.

There is no question that the Speed Pro and old TRW forged pistons are solid and reliable. They are stable and will take a lot of abuse. Literally millions of them have been put into service through the years. At one time they were the only forged pistons that were readily available for many engines. My gripe with them is mainly in two areas, weight and recently, cost.

The 318 piston/pin in the picture weighs 767 grams, according to the scale. Stock weight of a 318 piston is 591 grams. Stock weight of the pin is something like 170 grams. So the piston is a stock replacement weight.

Mopar pistons and connecting rods were nothing if they weren't heavy. The 720 gram 340 piston is my prime example. That's without pin. Another example is the LA's 645 connecting rod. At 758 grams, it is fat. Even the early 318 skinny rods were 726 grams. It isn't hard to buy a new rod at least 100 grams lighter. If you look you can shave off 150 grams per rod.

In Mark's Mechanical Engineering Handbook in the Automobile section I first ran across the concept that at a certain gear ratio it takes as much power to accelerate the engine rotating parts plus rotating parts of the drivetrain as it takes to accelerate the entire mass of the vehicle.

This puts a new light on rotating mass.

R.

They are already in there guys,
if the price is right, buy the thing, nothing wrong with them.
If starting new, that's a different thing.

Mark's Mechanical Engineering Handbook in the Automobile section I first ran across the concept that at a certain gear ratio it takes as much power to accelerate the engine rotating parts plus rotating parts of the drivetrain as it takes to accelerate the entire mass of the vehicle.

The reason people run in light weight shoes instead of work boots. The reason Greek Olympians competed in the nude. (Filled up the stands too)
I could go on.

I guess the beef I have with that idea is a 440 with heavy forged TRW's will, in neutral, rev up from idle to 6000rpm in a fraction of a second. Astronomically faster than it will ever accelerate the car. If that's the case would lightweight internals make a difference on ET at the track? I don't have any practical experience to say yes or no but I would sure be interested if anyone knows of an article where someone built an engine with heavy pistons, ran it at the track then swapped in identical but lightweight guts and ran it again.

I'm sure there is a rate of vehicle acceleration that would be equivalent in terms of energy consumed to that required to accelerate the internals but that rate could be something imperceptible.

I used a set of TRW they were heavy and thick. But strong I had them milled to have a 340 zero deck with closed chamber heads

Not mine, heavy but a good deal at 250 shipped if on a budget and I think this number is a ihra? approved 340 piston.

https://www.ebay.com/itm/Set-of-8-Pistons-for-340-Chrysler-Engine-2332P-040/273013813461?hash=item3f90e430d5:g:BVoAAOSwXOhaUO4q&vxp=mtr