Inspite of Many others claim of a 20HP or maybe more raise- on modified heads by yourself, this is actually unachievable without having camshaft or pistons altered. Toyota has casted and machined all their four valve heads to pretty near and precise tolerances for Road (and rally) use. That's what https://blacktop-4age76022.blognody.com/26410669/5-essential-elements-for-4a-ge-engine-for-sale