Link2603 Posted August 12, 2011 Report Share Posted August 12, 2011 I have a pair of 799 that i am going to put on my truck. My question is if i get them decked or put a thinner head gasket on will this be to much compresion for my engine. I want to run 91 octane. Thanks for any help Quote Link to comment Share on other sites More sharing options...
Cramer Posted August 13, 2011 Report Share Posted August 13, 2011 They are the same as the 243's I believe just a different forgery producing them. They should be a +/- 64cc head. IMO I wouldn't deck them at all, or use a thinner head gasket. I would do some porting and polishing to them while you have them off, and only if needed shave some off. Without knowing your other mods, or plans of mods these are a good upgrade in heads for the added CR, and basically the same flow as the 317's. The reduction in CC volume should raise your static CR roughly .5. That will be close to being able to run 91 octane. With a good tune it is doable. I am sure that there are guys on here that have the setup you are going with, so hopefully they chime in and shed light on the real deal. Quote Link to comment Share on other sites More sharing options...
zippy Posted August 14, 2011 Report Share Posted August 14, 2011 Just by bolting those heads on you'll be around 10.8:1 or so. If you do anything go with a Cometic .040 head gasket, but I'm not sure I would do that even. 91 octane isn't much to run that compression on unless you have very good tuning. With good tuning you will see a very noticable gain in power from the compression, but without it you'll have alot of detonation and will see no more power at all. Quote Link to comment Share on other sites More sharing options...
Link2603 Posted August 15, 2011 Author Report Share Posted August 15, 2011 The only reason I say 91 octane is because that's the hightedt I can get from a pump in Oklahoma. I ve already decided on going na so my other mods are a fast 102 lsxrt intake with a 102 mm tb, comp hr275xr, 44 lbs injectors and I ve already purchased all the recommended trans parts. Also a yank pt 3600 conveter. I was just seeing if any other na guys did something like that was these types of heads. But I think with what has been said I ll just port and polish them out and leave it at that Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted August 15, 2011 Report Share Posted August 15, 2011 (edited) I've got 65 cc heads and running the .041 gasket. Love it, its the only thing that gives me any bottom end power what so ever. I'm running 93 octane with no problems, and getting away with 33 degrees of advance. If your looking for all the NA power you can get but have to be concerned with detonation consider upgrading to a e fan kit, e water pump, and at least a 160 stat with holes drilled in it. I'm going to test out a 140 marine stat to see what that does for me as well. As far as porting, for gods sake go to a reputable ls porter not your local hot rod shop. I always recommend TEA based on their track record, the results i have had, and their flow rates are usually equal to or better then other places with a smaller valve. I'm going to guess the 44 pound injectors will cover it, but barely. Consider a ford svo green top(52 pound) or a deka 60 pound(72 pound at our pressure). If your going to buy injectors anyway, I'd get something with a touch more room to grow. did you mean xr275hr cam? Thats a pretty tame cam and the street manners will be great. the lsxrt intake and that cam will make for some fun 60 foot times. I don't say it much but your converter choice is great. However with the thinner gasket and the lsxrt intake you could probably get away with a larger cam and still be happy. maybe a 226 ish cam, and if you wanted to upgrade the converter just a tad to 3800, i'd say go for the 228 cam. Hopefully zippy can give his opinion as well, but with the higher compression and only 91 octane maybe pick a cam that will net a 8.7 DCR, and it should be easier on the detonation Headers? Zippy tuning? WIth your current path, and a set of 28" tires, you've got a great shot a 12 second NA pass Edited August 15, 2011 by shadowsniper3006 (see edit history) Quote Link to comment Share on other sites More sharing options...
Cramer Posted August 15, 2011 Report Share Posted August 15, 2011 If your going to do a cam at all with those heads and intake setup, get one custom ground for it. This will also be the best time to upgrade the lifters, and get some good valve springs in there. Like Zippy said, Tuning has to be spot on. Quote Link to comment Share on other sites More sharing options...
Link2603 Posted August 15, 2011 Author Report Share Posted August 15, 2011 I did mean xr not hr. I read alot of post that zippy has wrote on and that's why o selected that c. The cam is already bought but now I'm thinking about switching. I'm willing to run octane booster if need be since the truck is strictly for play. I just wonder if zippy would be able to do a mail order tune on my truck. Other tuners have already told me that a live street tune is the only way to go with that intake and tb i have. The problem with that is I don't trust any of the tuners in Oklahoma. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.