Improving afr 290s - Page 2 - Chevelle Tech
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post #16 of 50 (permalink) Old Oct 4th, 19, 10:35 PM Thread Starter
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Re: Improving afr 290s

They can get a spring on there that suits you. I had a pac flat tappet spring put on.

Strokerboats know of anyone that can do a decent valve job out this way (hemet) not one person in town can and dont want to drive 130 mi ea way.
Just basic stuff..surface, basic block stuff etc.

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post #17 of 50 (permalink) Old Oct 4th, 19, 10:46 PM
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Re: Improving afr 290s

I'll do some research and pm you.
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post #18 of 50 (permalink) Old Oct 5th, 19, 1:51 PM
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Re: Improving afr 290s

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Originally Posted by cuisinartvette View Post
They can get a spring on there that suits you. I had a pac flat tappet spring put on.

Strokerboats know of anyone that can do a decent valve job out this way (hemet) not one person in town can and dont want to drive 130 mi ea way.
Just basic stuff..surface, basic block stuff etc.
The valve job is probably the most critical part of that head's performance. Don't just send them to someone who can "do a good valve job"...send them to someone who know what they'r doing and who can duplicate AFR's valve job. The angles and width of the angles is very important and maintaining good concentricity, and keeping the depths equal is also important. I'd say probably 1 in 500 shops in this country can to that kind of work. Otherwise, just buy them and run them. Shipping is cheap. You can pretty much ruin the heads with a "decent" valve job.

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post #19 of 50 (permalink) Old Oct 5th, 19, 2:17 PM
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Re: Improving afr 290s

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The valve job is probably the most critical part of that head's performance.

Agreed. The shop I work with will examine the AFR valve job and guides and improve as needed. They also have a busy flow bench and they'll flow them and port match them to my intake.

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post #20 of 50 (permalink) Old Oct 5th, 19, 4:52 PM
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Re: Improving afr 290s

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Agreed. The shop I work with will examine the AFR valve job and guides and improve as needed. They also have a busy flow bench and they'll flow them and port match them to my intake.
Port match the heads to your intake? That would be interesting. If it's a rectangle intake, don't. If it's an oval port intake, you can't.

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post #21 of 50 (permalink) Old Oct 5th, 19, 5:42 PM
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Re: Improving afr 290s

Scott, I guess I got that backwards, I'd port match the intake to the heads. I'm using an oval port intake.

I wouldn't assume an intake will perfectly match the heads so while I have the valves out, it's a no brainer to bolt them up to check the ports.

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post #22 of 50 (permalink) Old Oct 5th, 19, 5:55 PM
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Re: Improving afr 290s

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Leave them alone. That's about as much air as you want to try and shove through that port architecture. The 300's flow more air but are horribly unstable and turbulent. 360-370cfm is enough for well over 800hp. You will do better to spend the time on getting the intake to fit the openings in the heads and make a nice transition in the intake runner. The "ROval" port opening in the heads has a lot of area and will more more air than most oval port intakes are designed to move. If the Edelbrock TR is a street oval port TR, you should port the entire runner to make it "right".
Can you elaborate a bit more on the AFR 300's? Is the turbulence in the port itself, or in the chamber? Or is it turbulence after the intake manifold port because the transition is typically so bad?

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post #23 of 50 (permalink) Old Oct 5th, 19, 6:09 PM
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Curious as to why you'd want to find a shop that can duplicate the AFR valve job if it sucks?
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post #24 of 50 (permalink) Old Oct 5th, 19, 7:46 PM Thread Starter
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Re: Improving afr 290s

Think he means if I need to stick guides or liners in them it.
Also I may/may not have to get similar work done on some of these import heads if I keep playing with them ones bound to be bad

Got your pm thanks. I had a high end place do a vj...aside from the one that leaked it was the wrong one and i lost almost 20cfm I know what youre saying.

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post #25 of 50 (permalink) Old Oct 5th, 19, 10:03 PM
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Re: Improving afr 290s

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Curious as to why you'd want to find a shop that can duplicate the AFR valve job if it sucks?
It's the quality of the valve job that would be in question, not the design. Concentricity and consistency of depth from cyl to cyl. The angles are not something you want to change unless you know what you're doing.

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post #26 of 50 (permalink) Old Oct 5th, 19, 10:08 PM
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Re: Improving afr 290s

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Can you elaborate a bit more on the AFR 300's? Is the turbulence in the port itself, or in the chamber? Or is it turbulence after the intake manifold port because the transition is typically so bad?
It's in the port itself. The opening of the port in relation to the deck is very low which makes the short turn transition very abrupt and just doesn't lend itself to a lot of airspeed. You can make the ports big and move a decent amount of air, they're just going to get unstable and turbulent at some point and not much you can do about it.

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post #27 of 50 (permalink) Old Oct 5th, 19, 10:10 PM
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Re: Improving afr 290s

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Scott, I guess I got that backwards, I'd port match the intake to the heads. I'm using an oval port intake.

I wouldn't assume an intake will perfectly match the heads so while I have the valves out, it's a no brainer to bolt them up to check the ports.
You'll want to have the heads bolted on the block you're going to run with the head gasket in place (or shims the same thickness) and a pair of intake gaskets in place in order to really know how the ports are going to line up.
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post #28 of 50 (permalink) Old Oct 5th, 19, 10:25 PM
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Re: Improving afr 290s

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You'll want to have the heads bolted on the block you're going to run with the head gasket in place (or shims the same thickness) and a pair of intake gaskets in place in order to really know how the ports are going to line up.

Yessir, that's how it's done.

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post #29 of 50 (permalink) Old Oct 6th, 19, 2:59 AM
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Lightbulb Re: Improving afr 290s

It'd be great to have Tony (formerly of AFR), who designed their Oval Magnums, as well as various noted engine builders, provide some additional perspective on the 300 Ovals to what has been said

Member Stokerboats has something of value to add on the 300s, I'm sure.


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post #30 of 50 (permalink) Old Oct 6th, 19, 3:18 AM
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Lightbulb Re: Improving afr 290s

AFR guy here, but...

This head is sure worth comparative consideration by the discerning...


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