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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
As some of you may know I picked up a pair of bare Assault Racing heads about a year ago and built them with parts from Competition products and Comp cams. Well fast forward to now. I dropped them off at Lloyd Elliots yesterday. Going to have the ports cleaned up and a custom valve job done to them. Also going to get them flowed before and after. When they go back on the Vortec 350 in my Express van they are going back on with a ported chinese stealthram. I wonder how close I can get to 500 hp with a 215/224@.050 cam and race quality intake/heads and exhaust? With 1.7 rockers that cam is more like 220/230 @ .050 and has .578" lift. I am going to guess those heads will be in the 280-290 cfm range when they are done and probably 190-200 on the exhaust. I do know with the 5.13 rear gear and only 31.5" tall tires that big heavy brick is going to run.
I talked with Lloyd today. Will have more information when I pick them up and have the actual flow chart but the out of the box heads with out of the box competition products valves were 244/170ish at about .600" on his flow bench. Ended up in the 290/190 cfm range at 0.600. I know that is a little more lift than I run but I know they have more potential later on to go on a bigger engine with more cam. I am hoping he flowed them at numerous lift points but I will say an improvement of 50 cfm on the same flow bench is an impressive gain. I am pumped to get them back and see how it runs when I get them on. Should make for one hell of a strong running 350 Vortec. Especially considering people are seeing 380 rwhp on his LE2 heads with a 218/224 cam and these heads with their 2.02/1.60s outflow the LE3s with 2.055 on the intake and as well as the 1.6 valve LE3s on the exhaust! He ended up setting the springs up to give 150# on the seat and 375# open with my cam specs. Should be able to turn 6,500 without valve float although I am sure that cam will be done making more power in the 6,000 rpm range.
I also found for the sake of comparison info given out by Lloyd years ago on stock aluminum LT1 head flow on his bench. Stock aluminum LT1 heads allegidly flow about 215/150 on his bench. These are also numbers straight from his website.
LE1s ~260/180 w 1.94/1.50 valve
LE2s ~275/190 w 2.00/1.56 valves
LE3s ~280/195 w 2.055/1.6 valves
I asked him how they compared to the LT1 heads. He said the Assaults have a raised port and bigger port and have what amounts to more material in the right places to be able to get more out of them than an OEM casting.
Also to me worth mentioning it seems he gets about 290/210 out of what he says are fully ported LT1 Trickflow heads with the 2.02/1.60 valve sizes and right at a 210cc intake port. That is also a $$$$ bare casting, not a $200 ebay part.
That being said the small cam he has ground for the LT1s is 218/224 on a 111 lsa with about .570 lift and Lloyd says it is good for 370-380 rwhp with the LE2 heads.
Yes it did make a difference. Problem is now i want to top this engine off with a FIRST TPI intake. Should make for a pretty quick Express van with an ordinary 5.7 Vortec bottem end in it.
The 862s should also make for a pretty quick 6.0L G20 Van. Should get that LQ4 up to about 10.5:1. With a nice cam in it, the 6.0L should make ~400 rwhp. It has had stock 862s on it for a year and ran great as it was.
Look pretty good. Floor at the short turn looks high and alot of turn angle. Could be the pic but if not i would have thought the floor would be lowered over the turn
i hate trying to get headers for square ports lol but alot of heads do that
While I have not yet had a chance to drive down and pick these up from Lloyd yet he did email me the numbers before and after.
BEFORE
LIFT------INTAKE-----EXHAUST
.200----------135-------103
.300----------183-------131
.400----------225-------150
.500----------244-------164
.600----------241-------175
.700----------241-------177
AFTER
LIFT------INTAKE-----EXHAUST
.200----------138-------107
.300----------192-------138
.400----------241-------164
.500----------274-------183
.600----------291-------193
.700----------295-------199
Those numbers are impressive for an inexpensive SBC head. After paying for all the parts and the name brand porting job how much did they cost you or at least how do they compare pricewise with a new set of AFR Eliminators?
Those numbers are impressive for an inexpensive SBC head. After paying for all the parts and the name brand porting job how much did they cost you or at least how do they compare pricewise with a new set of AFR Eliminators?
I think the total came to $1200 for the pair not including the time spent on the flow bench. You could build the set unported for $750. The unported numbers are really no slouch either. They flow what GM lT4 heads flow or slightly better. I would have to look at Lloyds invoice again to get the exact dollar amount. I had two sets of heads done at the same time and I forget the exact totals.
01-13-2019, 10:26 AM
