dizwiz24

I got an amazing deal on a set of AFR 210's (non-ported, pre- eliminator model). Heads are great. These are the 75cc big chamber heads.

I want to slap these onto my stock bottom end 93 lt1.

Its well-known that a loss of low-end, part-throttle snappy response is lost when going to too-big-a-head on a naturally aspirated setup.

However, this is not n/a setup. I have a p600b that usually makes 11 psi boost at 5000 rpm (on stock heads).

I called AFR and they think that, yes a smaller head would be better, but that I will appreciate improvements of this head vs. my stock heads.

They agree that boost may help the part throttle response vs. not having boost.

I also am putting in a 224/236 114 LSA .589/.589 -ish live cam in there w/ 1 3/4" long tube headers.

What are your thoughts?

I did some calculations and just dropping these heads on to my 350 lt-1 would yield a compression around 8.8:1 - too low.

I plan to mill heads to achieve a calculated compression of app. 9.4:1

I feel 9.4:1 will be a good compromise to help keep low end response and help the stock bottom end live a bit longer than w/ the 10.25:1 stock compression ratio.

Orr89rocz

You will be fine if you got the deal on these heads. They have small cross sectional areas for the size and high port velocities which makes them snappy compared to other heads of similar "CC" size. Also why they may be restrictive at high rpm on some combinations and cause power to drop off when they reach port choke sooner than other heads with larger cross sectional areas but similar cc sizes. It all depends on port shape

But I wouldnt hesitate to run those heads on an LT1 with that cam. I know guys running 220+ cc heads on 350-383 motors with good throttle response and make good power.

The blower is gonna offset any ill effect anyway

mzgp5x

Yes, I ran a p600b on a 97ss MM6 camaro for 3+ years.
AFR 190 heads with 55cc chambers. 350ci stock compression 10.5:1.
Also exhaust headers and a Crain Cam 218/ 218 .498lift (116lsa).
Very strong combination I thought. Killed many Porche 911's and such.
Don't know why they picked on me.
I ran the mid size driven pulley. Small pulley would not work. Shaft size very small. (Saft Key) to small.
Hope this helps. B.

blown94

Those heads are probably going to net you a little hp, but i dont think yer going to see much performance increase over stock heads/compression. You wont see much boost due to the higher flow rate of the heads, but that doest mean they aint makin power. Theyre definitely not optimal for that charger. Getting them cut down is a must to bump compression up, or get a D1SC, which would work much better with that head/cam choice. If i were you I would get a custom cam for that setup if you insist on using those heads as i think that cam and heads together is going to hurt you due to the lnger duration and largeness of the runners.

96capricemgr

IMO will you be happy and is it an effective setup are two separate questions. You think you bought good parts so you are going to be happy.

Orr89rocz

Guy I know ran a P600B on a 383 with afr 195 heads and similar cam and went 11's at 120+ mph at 5800+ ft (bandimere). Blower is small for the combo but it will work. He spun the crap out of the blower and still saw 9psi after the intercooler on that 383. Motor supposively dyno'd 530 on engine dyno before the blower.

210 AFR's arent huge heads for a 355 with good cam/intake. They will make hp over stock heads and a good bit too.

blown94

Exactly, he used a similar cam on a 30ci larger engine, with afr 195 heads, which is a more correct combination of parts to get the most out of it, but i dont know about making 530 hp before the blower, but its possible i guess?

Either way, point is you dont need a lrg cam with lrg runner heads on a small cube engine with a small blower. Its the biggest mismatch of components you could possibly put together IMO. Will it run, sure it will, but i would guess yer leaving alot of power on the table with the poor combination of components. You can spin a blower faster but it doesnt always = more power, instead it creates more heat. IMO the overall performance of this setup is going to be poor.

96capricemgr

530 flywheel really isn't that much. One "reputable" vendors 440hp strokers routinely make 330 at the wheels through A4s. Applying the same loss nets near 400rwhp. Probably better than most blower motors will make NA but not wild.
I would love to see what one of the 420+rwhp stock shortblock engines makes at the flywheel.

Just to be clear I put "reputable" in quotes above because I believe part of the issue is a dyno setup for advertizing and those motors tend to last under 7K miles. But I sight it because they are the most prolific generator of LT1 flywheel numbers we have to look at.

Orr89rocz

Yep 530 is stout and does seem optimistic for a typical blower engine. I plan to dyno my 401" motor with 245cc heads and 246 deg cam all motor just to see what it does

I've seen 369" motor make 535 on a dyno with midlength headers and a 233/233 custom cam with AFR 195 comp ports. With a single plane carb intake. With a custom EFI intake and some tweaking it eventually made 420whp thru locked up 4L60e/700r4 trans.
20% loss is a good estimate for auto cars.
A good designed cam in the 230's will do 530hp on a 383 with 195 heads that are worth a damn, but I dont think his cam was in the 230's. I'll try to find out. I've seen another 383 with 195's on an engine dyno make 520's hp with a milder 228 deg cam so you can easily get over 500 with a proper built 383.

Either way with good heads/cam, it doesnt take much more boost to really start getting power out of the combination.