TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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You head guys are misdirecting the average engine builder by dismissing the swirl jobs entirely. I've got three small blocks running them and for use under 5000 RPM they seem like they would be more efficient than some stock heads. I drive my cars on the street, they never see 5000 RPMs. So what matter is flow up there? If you don't own any heads, I agree, don't buy swirlys,, If you have a set and they are not cracked, put your money in pistons and cams..If you haven't won a race by the time you get to maximum head flow---
i run 193 heads on my stock car small block 350 4 bolt main, with 480/480 hyrd cam. 1.94/1.60 vales .40 over K.B. flat top pistons ,vortec rods. tourqer 2 intake and headers ,84 camaro steel fly wheel , 650 double pumper holly, 5.5 lbs balancer . on 1/3 mile high bank track. the car comes of the corner really good but the end of the straight away it stops pulling about 5800 rpm. . but corners is were you wins races. this year i am putting 2.02 1.60 vales with 507/507 lift 247/247 solid cam, with 1lb balancer engine will be fully balance. to see if the top end will come around. Will this help?
what is the biggest lift you can run with the swirl port heads??? i am trying to deside what to run with my combo. i have a gm short block with 345np pistons and gm performance rods bored .30 over trying to deside between the 350 swirl port heads or the l69 305ho heads
what is the biggest lift you can run with the swirl port heads??? i am trying to deside what to run with my combo. i have a gm short block with 345np pistons and gm performance rods bored .30 over trying to deside between the 350 swirl port heads or the l69 305ho heads
Both the swirl port heads and L69 heads are limited to around .480" lift before you run into trouble. Sometimes its lower though so if you chose a cam that is close proper measurement is required. I would take either head to a shop and have the valve guides cut so you can run larger lift cams (this is prety cheap). If you are boarderling on lift you will also want to replace the pressed in studs for screw in units. Couple hundred bucks at a machine shop will set you up for good size cam.
I have a free set of 193s and considering a budget build with them an a comp 423-8 Hr retro roller 224/236 501/510 lift in a 355 with fletcher top pistons. don't mind putting a fee hundred in these heads if I had a direction or tips on whether this cam is too big or how of a valves and how much milling I can do to them.
No offense, but I think someone gave you a free set of boat anchors
If you know what your doing, they can be made to flow ok, and work alright for something like a truck build where you want both torque and some top end power.
Those heads will need a lot more work then theyre worth to work with that cam. Id move on and get another set of heads to work with. That cam is all wrong for the TBI heads. I have a small version of the XE roller cams, and those have a lot more lift under the curve, sort of speak. That cam is pretty big, and will want good flowing heads to go with it.
Well I've been out of the tuning/building arena for awhile but am starting to get the itch again and was researching threads when I came upon this one. One thing noone has mentioned in this thread is how much of a PITA it is to port ANY steel head due to all those tiny shards of metal!!! I do realize there is a certain satisfaction in modifying heads for better flow results, and the end result can be quite gratifying and measured by performance numbers, but I personally can't stand the hand cramps and cleanup afterwards! IMO stock junkyard Vortechs that are in abundance, matched with a summit brand, performer knock-off are the way to go if man-hours and limiting self sacrifice is a concern. Then again maybe I'm just whining....
