Steve, I assume the plates are necessary because of the reduced deck/head height, going from a 351 to a 302?? If the plates aren't used, the header tubes would hit the oil-pan and/or block?? GS, 'not avoiding your question, I simply don't know the answer. :confused: edit: ordered adapter plates today from Cheryl @ http://www.spdexhaust.com/.
Purple or Steve, was the issue of sealing between the spacer and head resolved? Did you guys use Permatex and is that working? Is 1-1/4" long header bolts the correct length needed? .3125" (header flg thkness) .375 (spacer) .125 (gasket) + .375 (minimum thread engagement) --------- 1.1875" = 1-3/16", round up to 1=1/4" header bolt length Can either of you confirm this? Thanks, Rick
I think that jim used two gaskets but I decided that I wanted to "glue" the flange to the head with high temp (orange) sealer and just use one gasket to seal the header to the flange. I wasn't sure if it would work but I have seen it done before, it did work but I only had my engine fired up for about 10 minutes before I discovered that I had a head gasket leak. I removed the heads and the flanges have stayed glued to them with no evidence of leaks and they feel like they are "glued" on there quite nicely!! I'm sure the two gasket method works fine but I just wanted to use one gasket. I am using 1 1/4" alan head bolts but I had to use a couple ARP (small head 5/16") header bolts due to such tight clearance on a couple of the tubes.
I have a Boss 302 & most of us use port plates because of the inherent low end driveability problems associated with the over sized ports. We use the red hi temp sealant between the port plate & the head & then use the header gasket between the port plate & the header & never have a problem of leakage. Remember, Boss 302s any many other cars don't use gaskets between the exhaust manifold & the head to begin with.
Interesting, Can you elaborate? What's the reason for the low-end driveablity problems associated with over-sized ports and how do the plates counter that? Still thirsty for knowledge - even at my age! Thanks, Rick
On the Trans Am cars, Bud Moore actually built up the ramps on ports of the Boss heads because of poor low & mid range RPM performance. It especially effected the cars coming off the corners. The ports were just to damn big! Now, that affect is magnified significantly when your dealing with a stock Boss 302 engine. That is one of the reasons that the Aussie 2 barrel Cleveland heads are so popular. There are several companies out there that sell port plates for the big 4V Cleveland heads for under a $100. It's a considerable savings compared to the extensive work required to raise the floors of the ports in the heads. The port plates are 4 plates that install between the intake & exhaust manifolds(or headers). They have a specifically shaped tongue that enters each port on the intake & exhaust that effectively raises the ramp. The results are a significant increase in low end & mid range torque & power. I could go on & on, but those are the basic principles behind port plates.
Sounds similar to... ...some of the rumors that I have heard in the past about open headers and large exhaust pipes hurting the bottom end of mildly modified street engines. I have always heard that smaller exhaust pipes keep torque numbers up. I assume that the larger pipes and thus larger exhaust ports only help at very high RPMs. Is there any truth or relevance here? Seth
If I had a nickle for everytime I preached that sermon! .......Wait a sec.... What was the topic again?
I believe the Victor Juniors have the same port spacings as my AFR 185's. (I'd check into upgrading heads before spending the bux on the headers though - just my .02) I'd call Hooker to find out for sure on the fit. -Rick
