i was readin a thread a couple pages back about a converted LT4 intake on fast burns and got to thinkin. summit sells the LT4 intake for less than 250. Scroggin Dickey sells the fast burns i think for like 550 a piece. and i like the gm847 cam that a lot of lt1 guys run. i looked up some flow numbers for the fast burns and didnt find much but it was said they work well with larger lift cams. well the 847 cam specs out at 232-242 .575/.595 112LSA with 1.6 rockers. summit has it for 270 plus springs and rockers and such.

thats around 1816 plus about another 150 for springs if needed. now thats bear bones parts and prices there but 2k or so for heads and cam isnt bad.

my quesiton is, would this be a good setup for closer to 400rwhp with appropriate supporting fuel and exhaust mods with a t56? i know some have gotten close to 350rwhp with this cam in a stock headed LT1. and the fast burns would be ported so...

 

If 400 is all you are gunning for, I would think Vortecs would be a more appropriate choice. Vortecs would promote higher velocity and better flow up to around .400 lift. I've read at one time that this range is the majority of time at which your valves spend this time, though I don't know if that is true. .400 lift is roughly the point at which the Fast Burns outpace the Vortecs. The upgraded vortecs are something like $650 I think? A good deal if you ask me and the port dimensions are similar if not identical to the Fast Burns.

 

400 isnt exactly the goal but i didnt want to be too generous with the numbers. think this setup could make more? another reason i like the fast burns is the porting ability plus if i were to upgrade the bottom end and go with a higher compression the aluminum heads would be more pump gas friendly. thanks thus far tho.

*EDIT* the goal is more than likely around 420+rwhp on a 350 or close cubic inch engine NA. LS1s do it all the time on 346 cubic inches with better heads but i think a streetable 350 can do it too. i also want a slightly higher powerband than what most on here want. i dont want a whole lot of low like most do.

 

As far as my opinion of your above setup, I think it sounds pretty good. As far as the compression and the porting potential of the Fast Burns versus a similar head (I forgot GM offers a 200 cc iron vortec head these days), comparing apples to apples would reveal that the extra point in compression is needed to keep up with iron heads due to heat retention charactersitcs of the iron heads. Aluminum is easier to port, but I imagine it can be done to iron as well. 1bad91z has one heck of a motor with vortec heads that really flow

LS1's make 420+ rwhp often enough yes....but they are modded too. On a sidenote, there are many great things about the LS-based series of motors besides just the heads. If you wanna keep up with LS1's you will probably need more than a good set of heads, though that is a good start. I actually started out doing what you are doing with the intetion of wanting to keep up with LS1's, and then I found myself in big block territory (costwise). Guess which way I am going?

Good luck with your build!

 

Just a few things that I'd be concerned with, 210+ cc intake runner heads on a 350 is really going to kill any air velocity, not as much of a problem at higher rpms, but at a point its just going to suck when your not on it. Also I'd be concerned about reving a stock bottem to 6500 rpm. Probably need at least a 3500 stall too.

I think you might be better with AFR 195's or for another couple hundred, get more flow with the AFR 210's. ALSO if your still on a stock bottem end, compression is an issue. stock gaskets are .019" thick, most gaskets for use with aluminum heads are at least .039" so you'll lose ~.4-.5 in c/r even from your tractor fuel compatible 9.3 to 1, definitly not good with a good sized cam like that and aluminum heads. IMO use cast iron heads and a .015 shim gaskets to get your compression to 9.4-9.5 or mill the heads to 54-58 cc's and live with them later when you build a new motor.

The cam's big, but its possible to be tuned around. I don't have any experience tuning with that big of a cam, but I should soon enough. Also, I don't think someone like ed wright could burn you a satisfactory tune through the mail, but thats just my opinion.

Also, I'm curious why you want this particular cam. You could get a custom ground cam from comp cams for not much more. I believe if you order through summit they're under $300. Its hard to beat a hot cam when your saving nearly $75+ on the cam that works with stock heads, but the 847 isn't exactly a steal at $250+. What can I say, I guess I'm not a fan of GMPP cams.

 

actually this is exactly what i was looking for. it brought up several points that i hadnt thought about (like compression) and further pushed some quesiton i had (revving stock bottom end).

i would rather lose a few points on the low end and gain some up top because i actually want less torque. i would rather have a broad powerband that leans more towards the hgih side in an attempt to help with traction from a dig and racing from a roll. the stall doesnt bother me because no matter what i plan on a t56 swap.

the compression loss may be enough for me to scrap this idea. something ill need to think about.

as far as tuning theres a guy on our board (www.mofbody.com, yup im a member, same name actually) that said he would tune for me for a good price. hes already tuned his 91 355 z28 with this cam, majorly ported stock iron L98 heads and a HSR with his auto. i figured if i used the same cam it wouldnt be too hard for him to tune it because he already has.

i used it because before you mentioned custom grind prices i thought this was pretty cheap. i hadnt looked into custom grinds enough to know their prices. and this seemed to give the lt1 a powerband similar to what i wanted so i picked it. now ill need to rethink it. i hate the hot cam. im lookin to run mid 11s or better with a nice street 350 (might be on crack but i think it can be done) and be decent to drive every so often. (i have another vehicle to daily drive) so lots of lops and high gears really dont bother me much at all right now.

 

Ya, batchfire on there, I wouldn't mind meeting the guy and checking out his setup, I may be making a trip to KCIR sometime in about a month when I've got the new motor in, hopefully be able to meet up with some people.

About the heads... when I borrowed a guys engine stand tonight (thanks ray!) he said that he ran the .015 shim gaskets on his car for over a year without any problems. He's running aluminum L98 heads and was concerned about the shim gaskets too, but talked with his machinist and several other people and they had all had good luck with them even on aluminum heads. Said he'd even got it over 260 degrees once and never had problems. 9.4-9.5 to 1 is still too low of compression with aluminum heads.

IMO, do a leakdown test and/or compression test and see how your motor's holding up. If its not in good shape just save up, do it all at once, and start fresh. If not I'd go looking at some iron heads


Just something to keep in mind... the widest power band is going to be from undercamming some great flowing heads, allowing the engine to rev higher in the rpm band then the cam really wants to under normal circumstances. A big cam on decent heads isn't really going to give a broad power band, its going to be peaky without a whole lot of low end and nothing until uptop. When you start running a cam that wrings every last hp out of a set of heads, you really kill low end and midrange in order to get that last 20 hp out of the top end. In this situation a smaller cam may get more average hp "under the curve" and actually run faster at the track with less peak hp.

 

ya dustin is a good guy, definately knows his stuff. i havent seen his car yet but i should when he goes to tune my car after the fuel pump is fixed.

as far as the shortblock im kinda scared to see what shape its in...lol. it was SUPPOSED to have been rebuilt shortly before i got the car. but we all know how that goes.

now provided its in good shape should i look at different heads all together? im really not a fan of the vortec heads because they are stock type heads. its just a personal thing that i dont like modding with stock parts. what about the trickflow 23° heads? ive been lookin at those also and they seem to be pretty good. as far as powerband i would still think you would want a slightly large cam to bump the powerband up in the rpms. maybe not something that will ring out every last hp but somethin that will come close. what about the cc306 with the trickflows and an lt1 intake instead?

i ask about preground cams mostly because ive seen what they can do on lt1s. the 306 and the 847 both put down numbers like i like but more importantly are revved to about what i want.

 

The trickflow's are still aluminum heads and are going to have the same compression issues. You may call a couple machine shops around KC and see what they run to mill heads. milling them to 58 cc's would get your compression at 10.0 which should be enough. 54 cc's would get 10.5, but if you ever build another motor they might be hard to reuse and real hard to resell. The best route may be get some iron dart's or other brand and spending some money to get them ported by a legit head porter.

Either cam is going to be pretty big and probably do what you want to do, maybe just me, but I like pick my own cams, thats why I went with cam motion on my new motor. That and the lunati was going to take 2-4 weeks for summit to ship a cam that's in lunati's catalog. I'd pick the 847 over the 306, but thats just me... Another cam that'll work for you is a comp cams xe288, its 230/236 and either 110 or 112 LSA would work for you, but the 112 lsa might be the way to go if you like power brakes.

 

well i took the car to the track sunday and went 12.80 on the motor and 11.90 on a 100 i think that i am going to switch to some afr 195s milled to 60cc my compression is to low