More About Speedway Motors 461 Aluminum Small Block Chevy Heads for a 400. Check Stud torque.

[@pontiac411]

Ran multiple sbc 400 blocks, never drilled sream holes, never had cooling issues.. compression 12 to 13.1 with nitrous.

[@silverstreak232]

I understand that a lot of race engine builders drill and tap the steam holes for plugs.The main focus here is street use where the RPMs and coolant circulation will be lower, for longer periods of time, than that of a racing engine.

[@b.c4066]

@@silverstreak232 a higher flow water pump higher system pressure can accomplish the same results, most professional sbc head porting guys do not drill the steam holes anymore, even when using a stock 400 block for hot street builds like you are doing.

[@ricktaylor3748]

And, your heads ran hot, the steam ports are there of a reason.

[@tommywicker1432]

I didn't have issues either with or without nitrous which was a big direct port system. All in a destroked 400 , several destroked 400s

[@shootermcgavin2819]

​@@tommywicker1432 and reducing your cubic inches will ALWAYS yield you less power..

[@andrewmogi2178]

With the multi piece guide plates it affords the ability to individually center up the rocker arm over each respective valve stem tip before the stud is torqued to spec.

[@dougcrosby6994]

Several folks in the comments have alluded as to why the studs and guide plates are loose. I'll add that the "fingers" on those guide plates often need ground to allow enough movement to properly align the rockers and valve tips. I go a step further and tig weld them once locked in place. I also stamp (number) them and the heads so if they ever come off for service down the road they'll easily go right back together. Neat heads. LOTS of improvements to be had with porting. The aftermarket aluminum heads leave a good bit of material in the right places!! Unlike the old factory casings. Also, I've built plenty 400 small blocks and I've never drilled steam holes in the heads. Never had a cooling problem and I'm in S.E. Texas....plenty heat!!! I hope any of this helps someone out. Good luck on your build!

[@ronniecox109]

What temp does it run? The 400s ive seen with heads that were not drilled, were one pass wonders. One pass, and at 212 or better. If you do a block fill. Not so much of an issue.If I do a 400 block based engine. I use the DART SHP, block. 4.125 bore and a 4 inch stroke crank. = 427, 4.155,with the 4inch stroke crank= 434. My 81 malibu street/ strip car is a 427, AFR heads, K1 forged crank. And top of the line components thruout.

[@dougcrosby6994]

@@ronniecox109 I like to see mine run around 180ish. With enough radiator and fan (properly shrouded) it's never been an issue. I've built several. All different. Canfield heads, Brodix heads, Dart heads, etc... Several different things that will make em run hot. Not enough initial timing and shitty fans being the most common. I typically lockout the distributor and set it between 34* and 40* depending on where the best ET is found....then jet for MPH. Drivability is tuning pump shot, power valves and idle circuits. A start retard makes life on the starter and battery quite a bit easier. Tip: Look and the mid-late 90's Volvo dual speed fan!!

[@ronniecox109]

Also FWD Tarus duals work.

[@ImTheClay]

The reason the rocker studs are loose is because those are adjustable guide plates. You have to make sure the rockers are centered over the tips of your valve stems. If they tightened them up, it would probably be wrong for your engine. I do like that the have the double hump cast into the head, Thats cool.

[@randymacsgarage]

ditto

[@silverstreak232]

I have to correct one verbal mistake I made regarding the Aluminum head. At around the 9 minute mark I referred to it as a Summit head. Just to be clear these are Speedway's heads. My bad.

[@MVPisME383]

We always just use a head gasket with several head bolts through it to center it up to drill steam holes so you know without a doubt your in the right spot never had an issue just be sure to deburr it

[@silverstreak232]

I've used the head gasket method to spot the holes too. But, stick around and I'll explain why I'm going to make a jig plate for drilling the holes. At the moment I'm still waiting for a piece of aluminum flat stock to be delivered. I have all the other materials. If it's not something that interests you then by all means do what suits you.

[@randymacsgarage]

pretty cool explanation I retired as a cabinet builder turned hobby machinist got use to making templates👍👍 for cabinet stuff and the like carried it on to the machinist side of me and I dig it maybe you could prototype your jig and sell a few just sayin .

[@silverstreak232]

Thanks for the encouraging feedback. The reason for using the jig is to show others how to do a professional quality job, get it right the first time, using a hand drill. And the jig can be used reliably over again. Unfortunately, the cost of new materials (1/4" x 6" x 36" aluminum plate, drill bushings and screws) then labor would put the cost of a jig plate over $200 minus shipping. If I were to sell them, the costs out weigh the demand. When I proceed with constructing the jig I'll post it so others can follow along, if they'd like. The big plus is that once the jig is made, the job can be done right on the work bench. There's no need for a time consuming set up on a drill press or milling machine. And not everyone has access to a mill or large drill press.

[@tomtowers8513]

These Speedway Motors "461 heads" are just a Flo-Tek 180 casting head. The Summit "461 heads" are the Trick Flow 175 heads. These heads you have shown have adjustable guide plates as to why the rocker studs are not tight. I would also go over the valve job, check valve spring specs, guides. For a China casting its ok...the AFR Enforcer sbc head comes with steam holes for the 400 block and a good casting for the money...also a China casting.

[@silverstreak232]

Hi Tom, and thanks for the feedback. I understood that these were imports before buying. My main concerns are BUDGET and QUALITY. For the money, it was a toss up between the Edlebrock E Street heads and the Speedway heads. The Speedway heads were on sale at the time and were about $70 more than the USA made Edlebrock units. It was a hard a decision. The E Street heads have been around for a long time and have a very good reputation. In fact David Vizard devotes a section, to them in his book about porting and flow testing. He basically says they're really good for the money (not in those exact words). The Trick Flow double humps were just out of the price range. Since the Speedway product is relatively new to the scene and has some very good customer reviews (the basic Flow Tech units had some really bad reviews) I decided to go with them anyway. I feel they will look more at home on a painted street rod engine than the square looking E heads. AFR, although a great company with a great reputation was just out of the question as far as looks and price go. Guide plates. my experience with guide plates has only been with the one piece style as seen on factory SB Chevies. But, tightening and aligning them will be pretty straight forward. I was just surprised to see that the studs were practically falling out when I unpacked them. It might do Speedway some justice to make mention of this. Trust me. There will be someone out there that'll put these heads on a motor, leave the studs and guide plates as is, then blame the company they bought the heads from for their screwup. Even though these heads are sold "assembled and ready to go" I am going to pull the valves and hand lap them myself after doing a leak test on the bench with fluid. Then a leak down test can be done on the engine. Again, Thanks for your comment and have a great day.

[@glennbellman1100]

Those guide plates can be adjusted side to side for pushrod alignment.

[@derticktilghman5545]

They left them loose for you to set the setting of the pushrods/ rockermarms to the center of the valve stem.

[@johnsmithson2506]

Left them lose for reason to adjust for push rod clearance

[@MrHowlor5]

Would have liked to see more on jig.

[@silverstreak232]

@MrHowlor5 please bear with me. I'm am getting to the jig. Life threw some major changes my way and some of the adjustments are going a little slower than I'd like. In the mean time I'm completing work on the roadster that the old 400 will eventually find a home in. Thanks for the feedback and have a good day.

[@joedrt0013]

Hav that book.... M doin a 400 rite now👍💯

[@silverstreak232]

I have it too! What a coincidence 😁

[@RonaldLewis-py6yt]

Good review, looks like they will make way more HP than Ole doubble humps,you gona run flat top forged pistons, i got a 400 sbc i want to make 400 hp for towing!!

[@silverstreak232]

The 400 short block I'm using was assembled a LOOOOOOONG time ago. 1989 to be exact. It was a graduation present. Which in itself is a long story........ So, that explains the parts I'm using. The pistons are TRW #L2352F .030 over forged 1970 style dished. that yield 10:1 with 64cc chambers. The cam is an old Weiand #8102 hydraulic that was a match for the the Xcelerator 7546 intake. So, that's what I have. 400 horses seems like a high number. I'd be adequately happy with that. I expect the torque numbers to far out pace the peak HP. It's a street rod motor. All that aside, for towing, you have a good start. It might be more to your benefit to stay on the conservative side with the compression. Even the TRW #L2410F 1973 style 8.2:1 pistons produce 9.7:1 with 64 cc heads. This might be acceptable with aluminum heads and the right cam (110 to 112 LSA). Thanks for the feed back and best of luck to you.

[@RonaldLewis-py6yt]

@silverstreak232 my block is 511 still has oil and filter on it, standard dish pistons, I want good pistons and aluminum heads ! Thanks for your help 👍

[@silverstreak232]

​@RonaldLewis-py6yt Mine is a 511 casting also. It was cast in late 72. It has 2 bolt mains, contrary to popular belief that 511 blocks are all equipped with 4 bolt maincaps. That's OK. when I first got the 73 Caprice It was in, I was 13 years old. The owner told my dad and I it was a 350. Well, anyway I'll avoid that rabbit 🐇 hole 🕳 for now. Because that was back in 1984 😂! That's a topic for another day!

[@jimreaume2937]

You can get away with just using the old head gasket and the dow pins to locate the gasket

[@silverstreak232]

You can do that. I'm making a jig.

[@jimreaume2937]

@silverstreak232 hey what works for you that's all that matters , most ppl forget or don't believe that the steam holes are important lol if there not there the engine will overheat no matter what you do.

[@stuartsullenbarger2023]

I'm running a .30 over 400...406...with sportsman cast iron heads that do not have steam holes...I've never had a problem with overheating and that was the whole purpose of the steam holes...soo why bother.

[@silverstreak232]

It is not so much over heating being the big issue. It is low, coolant circulation at lower engine speeds allow steam pockets to develop under the block deck between the cylinders. I mentioned this. Engines that generally run at HIGH rpms most of the time don't need them. All that is explained in great detail in anything published by reputable sources concerning the SBC. I HAVE seen blown head gaskets where persons have tried to get away with omitting the steam holes on 400 blocks meant primarily for street use. That's why I'm bothering. Now, if what you do works for you, that's fine. You don't have to listen to anything I say. But, I'm going with the steam holes.

[@superdog1964]

You can easily drill steam holes by hand, no problem. You can also NOT drill them and never have any issues? Even if you are running on the street with 12:1 pistons and red lights every 100 ft. 25 different couples can go on 25 dates with total disregard towards babies and "germs" they may or may not have. 24 of them will not have any issues, HOWEVER, the 25th couple ends up with twins, warts on things that shouldn't have warts and lots of time spent in domestic relations and family court. All of this could have been avoided by a few extra minutes to drill holes or just purchase and apply coverings and life would still be great. The same thing applies to steam holes on a 400 SBC. While kids are expensive? blocks, heads, cranks, pistons and rods along with all the other moving parts can add up! Keep your 400 happy with steam holes and when your attached drill is on the move, protect it too! It is much better to have something you may never need then need something you don't have. Simple, easy and cheap may save you a LOT of cash and time?

[@Stevesbe]

I had a zz3 crate engine and those heads were crap I put my edelbrock rpm heads on and it made way more power

[@silverstreak232]

A pair of zz style corvette heads were the first aluminum heads I bought to swap onto a 76 stingray with a low compression L48 350. Back in the late 90s. A high Energy 268 cam, a Holley 600, a Chevy dualplane highrise intake, and good exhaust really woke that car up. The only complaint I had about that swap was that practically the entire top end, valve covers, intake, gaskets, etc... all had to be chosen to be used specifically with those cylinder heads. a set of Richmond 3.90 gears and a 2800 converter really made it snappy. By the way. Those heads came new from the factory complete with the studs and guide plates torqued, in place, and ready to run. So, to anyone who thinks that engine building is above my head. Think again. @Osbshowersyndicate that doesn't refer to you. But somedays I get the most absurd comments. Have a great day and thanks for the reply.

[@ricktaylor3748]

The exhaust side is 7/32.

[@silverstreak232]

NO IT'S NOT. IT'S 1/4 "

[@ricktaylor3748]

@@silverstreak232 Measure to steam port hole in the 400 head gasket, they're 7/32. I've built dozens of 400 small blocks. Also, the water in the block has to flow through the drilled heads, and there's no use drilling the steam port holes larger than necessary.

[@silverstreak232]

THE HOLE DRILLED IN THE HEAD IS 1/4"@@ricktaylor3748

[@ricktaylor3748]

@@silverstreak232 Turn your caps off, it doesn't make you any louder. Why is the hole in the 400 head gasket 7/32 ? As I said, there's no use drilling the steam port holes larger than necessary.