speedster head info been working on a set
 

Wanted to share my thoughts and info so far on the speedster heads. I did a mild port job and there is lots of room. The CNC entrance ports are nice I just blended to them. The exhaust needed a fair amount of clean up in the bowls. (hard to see the real results due to shadows in the pictures. I also upgraded these heads to 2.19 intake and 1.77 exhaust valves. The speedmaster valve stems measure about .2405 and the replacement valves are .2415 if you make this switch prepare to hone all of the guides as I did. All in all I'm very pleased with the heads if the valve seats don't fall out like many of the other speedmaster products. FYI I have not yet completed the valve job so the pictures of the seats are as delivered.

Are there specific cross sectional areas at the throat, bowl, short turn, push rod bulge and port entrance? I have a set and the ports are on the small side relative to a 2.11" valve so I was wondering what size you are at using a 2.19" valve.

measurements
 

I can measure the cross sectional area but I feel these are very similar to my edelborcks with 2.19 valves and they work great. For a street/mild race combo I like a little smaller port to help keep the velocity up. If these respond like other heads I think just changing to the 2.19 valve is good for about 8-10 CFM with the basically stock port. I don't currently have access to a flow bench to test these so I will have to do some real world testing once engine is in the car.

ports
 

I opened up the entrances to match the cnc openings taking out most of the pushrod bulge widening at the divider wall and raised the roof of the port. This is the same basic port entrance size that I use on the edelbrocks and the 1233 raIV entrance will support up to 335-340 CFM if everything else is good.

What bore size will be running?
Stock Block?

Combo
 

4.155 bore 4.25 stroke 6.800 rod. 988 400 block.

I bought a set of these during the sale and was wondering what guide plates do I need to get for them? Thanks.

A mold casting of the intake runner would be interesting; to report on the CSA vs length. I suspect the pushrod buldge would still be the Choke CSA

Velocity probing would in 10 seconds time prove out where the highest port air speed and hence restriction and in turn HP cut off would be found!

MPN: PCE251.1026

https://speedmaster79.com/Pontiac-32...Stud-Hole-1-Pc.

not sure why the URL is not working, but it is correct.

https://speedmaster79.com/Pontiac-32...tud-Hole-1-Pc..

Thanks, Eric

Would there be any reason not to use stock Pontiac guide plates? I have a set of these heads bare. I also have stock guides. Just wondering if I can use them

Also , is there a rocker stud length that is known to work with the 1.8-1.9 installed height valves or do I need to get the valves / springs first and then figure it out.

If that’s the case do I have to have the cam, lifters and pushrod length figured out also.

Thanks & Merry Christmas!
Murf


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Not sure about the heads over all but I can assure you the quality of the aluminum is good! I worked at an aluminum plant and Randy sent me a "chunk" of the head and I tested it... he has the results and it was posted here...

I checked the set I have with Edelbrock head guide plates and they line up. Not sure if stock will work.

stock Guide plates doing quite fit, they probably moved the valves like E-heads.

Thanks, I never thought of that. I better just order a set. They are plenty cheap enough.

I’ve had a bare set since last year & haven’t done anything with them yet.

I hope to have someone look them over & set them up for me sometime soon.

Would a machine shop have the spring locators on had or would I need to supply them? I thought I’d let them supply the valves & springs.

What about the head bolts? You guy’s that have installed a set of Speedmaster heads, did you get bolts from them or use ARP bolts for E heads?

Sorry about the 20 questions!

Merry Christmas!
Murf


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These are the head bolts I bought. ARP 190-3605, this is what they list in the description of the heads on the speedmaster site.

"if the valve seats don't fall out like many of the other speedmaster products"
This is what would worry me, save a couple of hundred dollars here and possibly lose an entire engine if a seat drops out. I've got a BBC here with Chinese heads -Speedmaster I presume- that a valve seat has dropped out, it's carnage inside, block/heads/crank/rods all scrap.

You are crushing peoples dreams. In other times the prices, their "Black Friday" would be called "dumping".
Sometimes the truth hurts.
Hey, I bought a 5 gallon Speedmaster fuel cell. It looks like I will use it after full inspection, looks good.
I also bought a "4340 billet" front T400 yoke. It was only 43$ so I thought "what the he!! "
Thing is, I do not think I will use it. Afraid. See, I have been running a factory Oldsmobile T400 front yoke that came out of a 455 station wagon. Its beefy and has held up to 10 sec runs in a heavy car.
So I know it works. If the "chinesium" 4340 breaks it will basically destroy my car. I have seen devastating carnage from front yokes failing even with safety loops.
I will just drop 200+$ on a USA made forging, or even ductile iron yoke before I trust my life and car to China,s best.
The heads are cheap enough that if mine, I would press out seats and have a good machine shop make sure its done right.
But then you are at E head price and why not give that cash to US factories in the first place.