Think I will do mine like the last pics.Cant hurt and shouldnt take long.

I changed my mind an picked up a set of slp's. I'll post some pics when I get them and finish the work. And i'm gonna be buying an tpis big mouth. They reps for tpis tell me it's and edelbrock but they port match and stuff, so whatever guys got 10 years ago is what im gonna be getting. Gonna hog out my slp's like the ones in the pics, hopefully i'll see a 40rwhp gain with headers, 3 inch ypipe, comp cams ultra pro magnum roller rockers, slp runners, ported plenum, ported big mouth, air foil, 24lb injectors, and a custom tune. I think i'll notice a significant gain in performance.

It should make for a good HP jump. i know i could feel a very good diff when i added march UD pulleys, ported SLPs/edelbrock base, and LTs on my truck....have yet to get it tuned also!
i will soon have my ported SLP/plenum up for sale....working on my SR now!

The "port matching" they do is so minimal I wouldnt even call it that.They prolly spend about 10 or 20 minutes on them.You`re going to want to open them up some more to see much difference.Remove the casting flash and polish the lower manifold.There is alot of room to remove material and increase flow,just make sure you`re doing it in the right places.I spent alot of time on my tpis lower manifold and its still not near what dyno don and them are doing on their stuff.I do believe we`ve much improved flow but i know there is still more to be had.With my cam and heads I think my lower manifold will suffice.

have any pics of your base? Im lookin to open my accel up but now sure how to go about it yet

Other than the pics in or around post 33 I dont have any more handy but,i should be able to get some soon.We just opened them up keeping the shape they have the best we could.I didnt do much to the underside where it hits the head until I get the stock intake off and take a look with the gasket and see what It needs.My buddy mike thinks its still much improved over stock cause he has R/R his brothers SR many times.He is running a 406 sbc with SR and unported accel base.So i think Mine will do fine for me.

Ya, I know it's gonna be the same. Hey how did your slp's match to the base. Cause I hear a big mouth gasket is offset from the slp gasket face.

Here's a pic that a professional porter sent me, he said this is a stock big mouth gasket that comes with the baseplate up against an slp runner and he just sharpied it in.. Tell me what you think.

Depending on how large you want to make the holes in the SLPs they might require a little welding. I have done a few sets and for max performance we weld them up and bore a 1.78" hole in them 1.75" deep and grind out the rest. We also siamese them with about 2" or less runner/divider left. There should be some pictures on this web site if you search for SLP an siamese.

I just want to port the big mouth a little bit and be able to completely match the slp's to them, i'd like an answer to my question of is the big mouth offset or is that just a false image of what the big mouth is like when bolted up to slp's...

You will se a significant jump in power and from what I have experienced you woun't be dissapointed. I have a high milage LB9 305 and did the following mods.


Edelbrock TES
3 inch Y flowmaster Y pipe/3 inch under the car/ Loudmouth muffler/ no Cats
Owner ported/simesed Plenum
Simesed / ported SLP Runners (not nearly as much as those shown earlier)
Simesed/Ported stock intake
adjustable regulator
1.6 Roller Tip rockers
underdrive pulley
de screened maf
gutted airbox/ K&N filters
air foil
160 Thermostat/cooling switches
Swapped T5 for T56
Harris Stage II chip


I went from 189 Hp at the wheels to 226 HP at the wheels. If anything you will get more than the 37HP I picked up. I have since added the Hawks cold air intake. You should get the 40 and depending on how well the porting turns out perhaps more.

I didnt see quite that much diff,but there is enough material on both sides to match them up.Seems to me someone wants your money.However he may do a better job than any of us....I DONT REALLY KNOW and you want know till you pay him.The best way to tell is to get your slp runners,order the gaskets and see for your self.I got mine to match but i did a little less porting on the bottom of my runners,than I did on the top.I have pics of them on page 1 around post 33 or so.I did not siameese the bottom of my runners.I have a small cam and revised casting(113) zz4 heads which just might be close to vortech heads.Maybe not ,thats what ive researched so we will see.

Ya, I can't see it being that far off, especially since it's an edelbrock casting. And i should be getting the big mouth in the mail in probably a month or so (i'm buying it friday and doing the cheapest shipping). And I plan on matching it myself, i'm good at porting. I just had it with the eddy's and decided to go with something that can outflow it big time. The top of the slp's where you can fit your whole hand in seems so awesome.

Got any updates?

The 113 heads wont make the power the Vortecs will unless Im mistaken the 113s go maybe 200cfm intake on a good day ex 160ish. Really need bigger valves to work well and a full port job the stock seats and intake port are horrendous. Have gotten 230ish int and 207 exh on a stock valve job/stock valve size and it took time to get there.
Those #s were at .600 lift honestly the lower numbers which matter werent that hot. A full port job with larger valves will make them work well but it will cost a nice chunk of change.

Getting to the middle turn of the runners is ideal that has to have an increase in size like the rest of the runner otherwise the work isnt really worth it. Either cut them open and weld up after or take the middle wall down use a 6" carbide and take your time. Even then hard to tell what youre doing.
Dont get too worried about a polished finish it wont run any differnet or make a bit more power. Also know that with a sand casting there can appear to be ample amount of material but if theres any type of void or air pocket in the casting its REAL easy to go through when, to the touch it really shouldnt have. What Im saying is unless its solid billet stock know when to say when
Been there done that.

Haha ive got updates. My intake was finished last year.
And now ive got a 385 that we're swapping in over Christmas.

Hows the intake breath for that combo?what all did you do to it port wise.Any pics?Sorry to revive the thread,I just ran across it again.

On the heads,I plan to get some when I can.I`m currently very under-employed so I gotta work with what I got.hopefully the intake will help some how it is.I`ve seen a few people run high 12`s on stock heads with stall/tires and such.If I can get close with what I got I`ll be happy.Its not a race car.
Im also hoping there is a little something to this thread.These are the ones I bought.I just didnt check anything before install.Will check them out when I can.

http://www.thirdgen.org/techboard/te...num-vette.html (WOW!!! GMPP Aluminum Vette Heads)