When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
To my knowledge, from my research on this thing for my future combination, no they dont really affect low-end that much, at least not for a streetable engine.
I am running the AFR rev kit. IT seems to work good with my 377. It pulls to 8000rpm+ pretty smoothly, but I can't compare to not having it because I have had the rev kit since the motor assembly.
I got the L98 AFR kit for sale if anyone is intrested. They work great for what they're. Don't expect them to replace/solve weak valve springs or cure valve float caused by nasty lobes with high ratio rockers and high RPM.
Just an installation tip: Go out and buy a valvespring compressor that is used for the old "flathead" Fords. It's cheap, available and most autoparts stores and will make your life alot easier.
or, you can just stack them together and sandwich them down tight as you slide the heads down onto the deck.
Reading these posts is soooo informative. Mine is bone stock with 106k miles on it. Runs like a champ (right now it idles poorly and I'm working on that) up to about 5600-5800 rpm. but just before it shifts (auto)...I get a mini-explosion (backfire) and she falls on her face for a milisecond then picks up strong again until I get to that RPM again. I've been thinking it was the rev limiter being out of sync with the shift point in the tranny...now I'm starting to think weak valve springs.