Anyone know anything about these heads?

[af2]

I hope you bought those. They were and are good heads. Have a few friends still running them in what I consider fast street cars.

[HQM383]

Back when they were current, I had a couple sets of the Jegs 197cc heads in the shop for a quick check over.
I remember thinking the flow was pretty mediocre at the time.......240’s maybe ??
It’s been ages since I had them here....... but I also seem to think the height of the intake SSR was rather low....... at least that how I’m remembering it.

The Jegs heads also had a core plug on each end of the head.

I’ll take them to MELWAY on this forum at Pro-Port CNC 20 mins up the road from me to be assessed to see how far I will go with them. For what I’m paying there won’t be any tears if they are a fizzer. Best case they fulfill my needs fo a while to run low 11’s in a 3350lbs street/strip car. Worst case I make them look pretty and flip them for some cash.

[HQM383]

I hope you bought those. They were and are good heads. Have a few friends still running them in what I consider fast street cars.

Yes I’ll be buying them. Probably end up to my door for about $400 total.

[steve cowan]

Back when they were current, I had a couple sets of the Jegs 197cc heads in the shop for a quick check over.
I remember thinking the flow was pretty mediocre at the time.......240’s maybe ??
It’s been ages since I had them here....... but I also seem to think the height of the intake SSR was rather low....... at least that how I’m remembering it.

The Jegs heads also had a core plug on each end of the head.

I’ll take them to MELWAY on this forum at Pro-Port CNC 20 mins up the road from me to be assessed to see how far I will go with them. For what I’m paying there won’t be any tears if they are a fizzer. Best case they fulfill my needs fo a while to run low 11’s in a 3350lbs street/strip car. Worst case I make them look pretty and flip them for some cash.

James is a good guy
He knows his stuff

[HQM383]

Got the heads. Look just like Canfields I’ve seen online with the freeze plug in the ends of the head. Done some quick measurements and mcsa ~ 2.0 sq in. Throat varied from 1.755” - 1.80” over different ports with a 2.02” intake which is around 89% for the largest. Don’t know the cc’s but someone might correlate those figures to an intake cc. Canfield done a 195cc and 197cc. Don’t know combustion chamber cc either but I’ll take them for a thorough clean and have them measured at the same time. A little bit of welding to be done but that’s not a concern.

Total cost so far $300 for heads, valves, retainers and springs. $85 shipping from Perth to near Melbourne where I am around 3,300km - 2050mi. So not too much invested yet.

[KnightEngines]

Good starting point, not too big, not so small you gotta hog a bunch out.
Use 2.055" intakes.

[Racer97]

I have the 197s with 2.055 valves on a 350 they work great. I did sand the ssr back and set the bowls to 90%

[PRH]

HQM...... do the intake floors and short turns seem kinda flat for an aftermarket performance head?

I haven’t had any of those in my hands in quite a few years, but for some reason that’s how I remember them.

[HQM383]

HQM...... do the intake floors and short turns seem kinda flat for an aftermarket performance head?

I haven’t had any of those in my hands in quite a few years, but for some reason that’s how I remember them.

Not too flat

[HQM383]

Good starting point, not too big, not so small you gotta hog a bunch out.
Use 2.055" intakes.

What would be the kind of mcsa and throat sizes for 383ci for peak torque around 4500rpm?

[KnightEngines]

Good starting point, not too big, not so small you gotta hog a bunch out.
Use 2.055" intakes.

What would be the kind of mcsa and throat sizes for 383ci for peak torque around 4500rpm?

Around 500-530hp @ 6000?
4500rpm peak tq should make peak hp at 6000 or thereabouts.
A 383 at 105-110% ve should make 500-535hp.

2.1" mcsa, 87% throat on a 2.055" valve.

[HQM383]

Good starting point, not too big, not so small you gotta hog a bunch out.
Use 2.055" intakes.

What would be the kind of mcsa and throat sizes for 383ci for peak torque around 4500rpm?

Around 500-530hp @ 6000?
4500rpm peak tq should make peak hp at 6000 or thereabouts.
A 383 at 105-110% ve should make 500-535hp.

2.1" mcsa, 87% throat on a 2.055" valve.

That would do me. Not after power for the sake of power. Just looking to do mid to low 11's in the coupe and drive around town whenever I want. Around 500hp and 500ft/lb should get me there.

[KnightEngines]

What would be the kind of mcsa and throat sizes for 383ci for peak torque around 4500rpm?

Around 500-530hp @ 6000?
4500rpm peak tq should make peak hp at 6000 or thereabouts.
A 383 at 105-110% ve should make 500-535hp.

2.1" mcsa, 87% throat on a 2.055" valve.

That would do me. Not after power for the sake of power. Just looking to do mid to low 11's in the coupe and drive around town whenever I want. Around 500hp and 500ft/lb should get me there.

Yep, 500hp will do the job.
Those heads can do it easy with just a little rub.

[HQM383]

Picked up these heads today from James. They have a flaw that is not conducive to performance without a lot of work. He spotted straight up what my untrained eye would have seen but not taken into account. But that’s fine as part of the reason behind buying these cheap heads is to learn what aspects of cylinder heads efficiently produce torque, power and drivability. I could throw some cash at a set of AFR heads or something similar with some research and advice from the good folks on Speedtalk to achieve my end goal but I would rather go through the development process to learn the hows and whys first hand (with a lot of help from the likes of James) of how I achieved my goal. On top of that, remembering this is for a street strip deal I don’t want to fork out the prices we pay in Aus for high quality 23 degree heads to find 23* don’t make the mid range torque of the Trickflow’s. If they do I’ll invest in top shelf heads knowing with a sharper focus what I require. If not then developing the Trickflow’s and the engine around them will be the path to take.

Anyway, what James pointed out with the Offy heads is that someone has plunge cut directly below the seat stuffing the throat and any chance of quality flow past the seat. I must have measured in the wrong places because this puts throat over 90%. Could be rectified but too much money and hassle considering the starting point. See pic below between arrows. James took the time to show me what a good throat and transition through the seat looks like and explanation of why on one of his cnc heads. Also another head bought to him for a cnc job after someone hogged them out and that will perform better with his work, but not as good as they could be showing me where excess material had been removed in places it should not be. Thanks James and Offy heads for lesson 1. These heads will eventually be used when I move on the short block I am using now or tidied up and assembled and sold as a pair of heads for someone looking for heads for a cruiser so they will not be money down the drain.

Big thanks to James who has spent time pm’ing on Speedtalk, chatting on the phone and in his workshop thus far and looking over the heads without asking for a cent. Appreciated, and I’ll be making sure some work will be coming his way in the near future.

First up is getting back to the track to get a baseline of where things are at now to gauge what impact changes have.